I Resistance Exercise - McMaster University
RESISTANCE EXERCISE REPETITION LOAD ON HYPERTROPHY AND STRENGTH THE EFFECT OF RESISTANCE TRAINING REPETITION LOAD ON MUSCULAR HYPERTROPHY AND STRENGTH IN YOUNG RESISTANCE TRAINED MENBySARA Y OIKAWA, B.Sc.A Thesis Submitted to the School of Graduate Studies in Partial Fulfillment of the Requirements for the degree Master of ScienceMcMaster University? Copyright by Sara Oikawa, July 2015Master University MASTER OF SCIENCE (2015) Hamilton, Ontario (Kinesiology)TITLE: The effect of resistance training repetition load on muscular hypertrophy and strength in young resistance trained menAUTHOR: Sara Y. Oikawa, B.Sc. Kin (McMaster University)SUPERVISOR: Dr. Stuart M. Phillips, Ph.D.NUMBER OF PAGES: xi, 57Lay AbstractResistance training (RT) results in an increase in muscle growth and an increase in strength. Previously, we have shown in young untrained males, that when exercise is performed until failure, or until the weight can no longer be lifted, that gains in muscle and strength were similar with the use of either light or heavy weights. The purpose of the study was to determine the effects of 12 weeks of RT on muscle growth and strength in young men who were already regularly participating in resistance exercise when performing either lower load high repetition RT (HR) or higher load low repetition RT (LR). Maximum strength and changes in muscle mass were assessed prior to and upon completion of the training protocol. Following 12 weeks of RT both groups increased muscle mass and strength to a similar extent with the exception of bench press which increased more in the LR group.AbstractResistance training (RT)-induced skeletal muscle hypertrophy is partly responsible for the RT-induced increase in strength. Previously, we reported that exercise repetition load played a minimal role in the promotion of RT-induced gains in hypertrophy and strength gains in RT-na?ve participants performing RE to volitional failure. Thus, the main aim of this study were to determine the effects of 12 weeks of RT on muscle strength and hypertrophy in a trained population. 49 resistance-trained men (mean ± SEM, 23 ± 1 years, 85.9 ± 2.2 kg, 181 ± 1 cm) were randomly allocated into a lower load-high-repetition group (HR, n=24) or a higher load-low-repetition group (LR, n=25). Repetition load was set so that volitional lifting failure was achieved within the repetition ranges of 20-25 (~35-50% of 1RM) for HR or 8-12 for LR (~70-85% of 1RM). Strength as one repetition maximum (1RM) was assessed pre and post. Changes in lean body mass (LBM), appendicular lean mass (ALM) and leg lean mass (LLM) were assessed using dual-energy x-ray absorptiometry (DXA). There were significant increases in strength in all exercises with no differences between groups (p > 0.05) with the exception of bench press where LR showed a greater increase in 1RM than HR (p = 0.012). Similarly, LBM, ALM, and LLM increased significantly following training in the HR group (1.0 ± 0.9kg, p < .001; 0.8 ± 1.1 kg, p < 0.05; 0.7 ± 0.9 kg, p < 0.01 respectively) and the LR group (1.6 ± 1.4 kg, p < .001; 1.0 ± 1.2 kg, p < 0.05; 0.7 ± 1.0 kg, p < 0.01 respectively) with no significant differences between groups (all p > 0.05). These data show that RE performed to volitional failure using either HR or LR induces similar adaptations strength and lean mass accrual in young resistance-trained men. ACKNOWLEDGEMENTSI would like to acknowledge the following people whose contributions have helped to make this thesis possible:Stuart Phillips for every opportunity you have given me. The last several years working under your guidance have been indispensible. I am grateful and excited for the next 4 years and continuing to do some ‘cool science’.Mark and Skelly, from day 1 until the end, I don’t know what I would have done without you (and all the pizza). Without a doubt, the best teammates out there and I am incredibly lucky to have you both. Audrey Hicks, Gianni Parise and Jim Potvin for your guidance and serving on my committee. To the Phillips lab, Amy, Cam, Caoileann, Kirsten, Rob, Tom and Tyler it has been a pleasure to work with every one of you. Rob, for making this project possible.Chris and Michaela for your guidance and patience, thank you for always lending an ear. Todd and Tracy for all your help, technical advice and early mornings. To Chris Wavell, Nicole and our many volunteers, this study wouldn’t have been possible without all of your hard work and dedication.To the EMRG labs and the KGB, thank you for your support in lab and out, it has been a privilege to work with you all. Thank you for all the laughs and making these last 2 years so much fun. Looking forward to another chapter to spend with you all. Cam, thank you for helping me get my start.Lastly, thank you Mom, Dad, Lisa and Mark for your constant love, support, patience and allowing me to continue doing what I love. TABLE OF CONTENTSTitle Page............................................................................................................................. i Descriptive Note ................................................................................................................ ii Lay Abstract ...................................................................................................................... iiiAbstract.............................................................................................................................. iv Acknowledgements ............................................................................................................ vTable of Contents.............................................................................................................. viiList of Figures and Tables ................................................................................................ ixList of Abbreviations ......................................................................................................... xDeclaration of Academic Achievement ............................................................................ xiChapter I – Skeletal Muscle Hypertrophy and Strength with Resistance Exercise TOC \o "1-3" I Resistance Exercise PAGEREF _Toc296597625 \h 2IINeural Adaptions to RE training PAGEREF _Toc296597626 \h 4IIIProtein Synthesis and Hypertrophy PAGEREF _Toc296597627 \h 6III.iProtein Synthesis and Resistance Exercise PAGEREF _Toc296597628 \h 6III.ii Role of Protein Dose and Quality PAGEREF _Toc296597629 \h 10IVMeasurement of Skeletal Muscle Hypertrophy PAGEREF _Toc296597630 \h 13V Resistance Training Recommendations PAGEREF _Toc296597631 \h 17VIStatement of Research Question and Hypothesis PAGEREF _Toc296597632 \h 271.Methods PAGEREF _Toc296597633 \h 301.1 Participants and Ethics PAGEREF _Toc296597634 \h 301.2. Experimental Design PAGEREF _Toc296597635 \h 311.3Familiarization and Muscle Strength PAGEREF _Toc296597636 \h 311.4Body Composition PAGEREF _Toc296597637 \h 331.5Resistance Training Protocol PAGEREF _Toc296597638 \h 331.6Statistical Analysis PAGEREF _Toc296597639 \h 352.Results PAGEREF _Toc296597640 \h 362.1Participant Characteristics and Anthropometrics PAGEREF _Toc296597641 \h 362.2Strength Changes PAGEREF _Toc296597642 \h 372.3Volume of Exercise PAGEREF _Toc296597643 \h 392.4Discussion PAGEREF _Toc296597644 \h 402.4.1High vs. Low Repetition RT and Hypertrophy PAGEREF _Toc296597645 \h 402.4.2High vs. Low Repetition Resistance Exercise and Strength PAGEREF _Toc296597646 \h 442.4.3Limitations PAGEREF _Toc296597647 \h 462.4.4Conclusions PAGEREF _Toc296597648 \h 472.4.5Future Directions PAGEREF _Toc296597649 \h 48REFERENCES PAGEREF _Toc296597650 \h 49LIST OF FIGURES AND TABLESFigure i. Elevation of MPS following 48 hours, Churchward-Venne et al., 2012............. 9Figure ii. 2 and 3 compartment models of body composition.......................................... 17Figure iii. Percentage change in quadriceps muscle volume, Mitchell et al., 2012......... 25Figure iv a. Acute mixed FSR in the trained and untrained legs, Kim et al., 2005.......... 27Figure iv b. Acute myofibrillar FSR in the trained an untrained legs, Kim et al., 2005... 24Figure 1a. Individual changes in LBM in the HR group.................................................. 37Figure 1b. Individual changes in LBM in the LR group................................................... 37Figure 2a. Leg press strength changes in the HR and LR groups .................................... 38Figure 2b. Bench press strength changes in the HR and LR groups ................................ 38Figure 2c. Leg extension strength changes in the HR and LR groups ............................. 38Figure 2d. Shoulder press strength changes in the HR and LR groups ........................... 38Figure 3. Average volume of exercise performed per training session............................ 39Table i. Summary of literature on hypertrophy and strength adaptions to high and low repetition resistance exercise training............................................................................... 23Table 1. Participants’ characteristics at baseline.............................................................. 31Table 2. Participants’ body composition following 12 weeks of resistance exercise training.............................................................................................................................. 36Table 3. Participants’ strength following 12 weeks of resistance exercise training......... 38LIST OF ABBREVIATIONS1RMone repetition maximumALMappendicular lean massBFRblood flow restrictionCSAcross-sectional areaDXAdual-energy X-ray absorptiometryLBMlean body massLLMleg lean massiEMGintegrated electromyographical MRImagnetic resonance imagingMPBmuscle protein breakdownMPSmuscle protein synthesismTORC-1mechanistic target of rapamycin complex 1MUmotor unitMVCmaximum voluntary contractionPDCAASprotein digestibility-corrected amino acid scoreREresistance exerciseRTresistance trainingDECLARATION OF ACADEMIC ACHIEVEMENTS.Y. Oikawa was the principal contributor for the conceptualizing the research question, research hypothesis, experimental design, data collection, data analysis and data interpretation . S.M. Phillips, C. McGlory and M.C. Devries assisted with the research question, research hypothesis, experimental design and data interpretation. R.W. Morton contributed to the data collection and data interpretation. CHAPTER ISKELETAL MUSCLE HYPERTROPHY AND STRENGTH WITH RESISTANCE EXERCISEI Resistance ExerciseThe human body is comprised of ~45% skeletal muscle by mass ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "0002-9165 (Print)\\n0002-9165 (Linking)", "ISSN" : "00029165", "PMID" : "10966902", "abstract" : "BACKGROUND: Skeletal muscle (SM) is a large body compartment of biological importance, but it remains difficult to quantify SM with affordable and practical methods that can be applied in clinical and field settings. OBJECTIVE: The objective of this study was to develop and cross-validate anthropometric SM mass prediction models in healthy adults. DESIGN: SM mass, measured by using whole-body multislice magnetic resonance imaging, was set as the dependent variable in prediction models. Independent variables were organized into 2 separate formulas. One formula included mainly limb circumferences and skinfold thicknesses [model 1: height (in m) and skinfold-corrected upperarm, thigh, and calf girths (CAG, CTG, and CCG, respectively; in cm)]. The other formula included mainly body weight (in kg) and height (model 2). The models were developed and cross-validated in nonobese adults [body mass index (in kg/m(2)) < 30]. RESULTS: Two SM (in kg) models for nonobese subjects (n = 244) were developed as follows: SM = Ht x (0.00744 x CAG(2) + 0.00088 x CTG(2) + 0.00441 x CCG(2)) + 2.4 x sex - 0.048 x age + race + 7.8, where R:(2) = 0.91, P: < 0.0001, and SEE = 2.2 kg; sex = 0 for female and 1 for male, race = -2.0 for Asian, 1.1 for African American, and 0 for white and Hispanic, and SM = 0.244 x BW + 7.80 x Ht + 6.6 x sex - 0.098 x age + race - 3.3, where R:(2) = 0.86, P: < 0.0001, and SEE = 2.8 kg; sex = 0 for female and 1 for male, race = -1.2 for Asian, 1.4 for African American, and 0 for white and Hispanic. CONCLUSION: These 2 anthropometric prediction models, the first developed in vivo by using state-of-the-art body-composition methods, are likely to prove useful in clinical evaluations and field studies of SM mass in nonobese adults.", "author" : [ { "dropping-particle" : "", "family" : "Lee", "given" : "Robert C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wang", "given" : "ZiMian", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Heo", "given" : "Moonseong", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ross", "given" : "Robert", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Jannsen", "given" : "Ian", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Heymsfield", "given" : "Steven B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American Journal of Clinical Nutrition", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2000" ] ] }, "page" : "796-803", "title" : "Total-body skeletal muscle mass: Development and cross-validation of anthropometric prediction models", "type" : "article-journal", "volume" : "72" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[1]", "plainTextFormattedCitation" : "[1]", "previouslyFormattedCitation" : "[1]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[1]. Skeletal muscle is a critical organ that plays a key role in the generation of contractile force, post-prandial glucose disposal ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/physrev.00038.2012", "ISSN" : "1522-1210", "PMID" : "23899560", "abstract" : "Glucose is an important fuel for contracting muscle, and normal glucose metabolism is vital for health. Glucose enters the muscle cell via facilitated diffusion through the GLUT4 glucose transporter which translocates from intracellular storage depots to the plasma membrane and T-tubules upon muscle contraction. Here we discuss the current understanding of how exercise-induced muscle glucose uptake is regulated. We briefly discuss the role of glucose supply and metabolism and concentrate on GLUT4 translocation and the molecular signaling that sets this in motion during muscle contractions. Contraction-induced molecular signaling is complex and involves a variety of signaling molecules including AMPK, Ca(2+), and NOS in the proximal part of the signaling cascade as well as GTPases, Rab, and SNARE proteins and cytoskeletal components in the distal part. While acute regulation of muscle glucose uptake relies on GLUT4 translocation, glucose uptake also depends on muscle GLUT4 expression which is increased following exercise. AMPK and CaMKII are key signaling kinases that appear to regulate GLUT4 expression via the HDAC4/5-MEF2 axis and MEF2-GEF interactions resulting in nuclear export of HDAC4/5 in turn leading to histone hyperacetylation on the GLUT4 promoter and increased GLUT4 transcription. Exercise training is the most potent stimulus to increase skeletal muscle GLUT4 expression, an effect that may partly contribute to improved insulin action and glucose disposal and enhanced muscle glycogen storage following exercise training in health and disease.", "author" : [ { "dropping-particle" : "", "family" : "Richter", "given" : "Erik a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hargreaves", "given" : "Mark", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Physiological reviews", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2013", "7" ] ] }, "page" : "993-1017", "title" : "Exercise, GLUT4, and skeletal muscle glucose uptake.", "type" : "article-journal", "volume" : "93" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[2]", "plainTextFormattedCitation" : "[2]", "previouslyFormattedCitation" : "[2]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[2], and maintenance of this tissue is positively associated with metabolic health ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISSN" : "0002-9165", "PMID" : "16960159", "abstract" : "Muscle plays a central role in whole-body protein metabolism by serving as the principal reservoir for amino acids to maintain protein synthesis in vital tissues and organs in the absence of amino acid absorption from the gut and by providing hepatic gluconeogenic precursors. Furthermore, altered muscle metabolism plays a key role in the genesis, and therefore the prevention, of many common pathologic conditions and chronic diseases. Nonetheless, the maintenance of adequate muscle mass, strength, and metabolic function has rarely, if ever, been targeted as a relevant endpoint of recommendations for dietary intake. It is therefore imperative that factors directly related to muscle mass, strength, and metabolic function be included in future studies designed to demonstrate optimal lifestyle behaviors throughout the life span, including physical activity and diet.", "author" : [ { "dropping-particle" : "", "family" : "Wolfe", "given" : "Robert R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The American journal of clinical nutrition", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2006", "9" ] ] }, "page" : "475-82", "title" : "The underappreciated role of muscle in health and disease.", "type" : "article-journal", "volume" : "84" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[3]", "plainTextFormattedCitation" : "[3]", "previouslyFormattedCitation" : "[3]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[3]. Skeletal muscle is also a unique and highly plastic tissue capable of changing its phenotype in response to alterations in the load, frequency, and duration of contractile activity. The nature of these adaptions is, however, specific to the type of stimulus. For example, performing endurance exercise results in improved fatigue resistance due in part to an increase in mitochondrial density and oxidative capacity ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1016/j.cmet.2012.12.012", "ISBN" : "1550-4131", "ISSN" : "15504131", "PMID" : "23395166", "abstract" : "Preservation of aerobic fitness and skeletal muscle strength through exercise training can ameliorate metabolic dysfunction and prevent chronic disease. These benefits are mediated in part by extensive metabolic and molecular remodeling of skeletal muscle by exercise. Aerobic and resistance exercise represent extremes on the exercise continuum and elicit markedly different training responses that are mediated by a complex interplay between a myriad of signaling pathways coupled to downstream regulators of transcription and translation. Here, we review the metabolic responses and molecular mechanisms that underpin the adaptatation of skeletal muscle to acute exercise and exercise training. ?? 2013 Elsevier Inc.", "author" : [ { "dropping-particle" : "", "family" : "Egan", "given" : "Brendan", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Zierath", "given" : "Juleen R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Cell Metabolism", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2013" ] ] }, "page" : "162-184", "publisher" : "Elsevier Inc.", "title" : "Exercise metabolism and the molecular regulation of skeletal muscle adaptation", "type" : "article-journal", "volume" : "17" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[4]", "plainTextFormattedCitation" : "[4]", "previouslyFormattedCitation" : "[4]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[4]. In contrast, repeated bouts of high intensity, loaded contractions (i.e., resistance exercise), induces the rapid recruitment of type 2 fibers and an increase in muscle fiber cross-sectional area and a lesser stimulation of oxidative capacity ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-2", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5,6]", "plainTextFormattedCitation" : "[5,6]", "previouslyFormattedCitation" : "[5,6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5,6]. Resistance exercise training also induces favorable strength adaptations ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Sale", "given" : "DG", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and science in sports and exercise", "id" : "ITEM-1", "issue" : "5", "issued" : { "date-parts" : [ [ "1988" ] ] }, "page" : "135-145", "title" : "Neural adaptation to resistance training", "type" : "article-journal", "volume" : "20" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[7]", "plainTextFormattedCitation" : "[7]", "previouslyFormattedCitation" : "[7]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[7]. Thus, it is unsurprising that exercise, particularly resistance exercise, has long been utilized as an effective strategy to improve human health and athletic performance ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Delorme", "given" : "Thomas L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Schwab", "given" : "Robert S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Watkins", "given" : "Arthur L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Bone & Joint Surgery", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "1948" ] ] }, "page" : "834-847", "title" : "The response of the quadriceps femoris to progressive resistance exercises in poliomyelitic patients", "type" : "article-journal", "volume" : "30" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[8]", "plainTextFormattedCitation" : "[8]", "previouslyFormattedCitation" : "[8]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[8].Resistance exercise (RE) is the only non-pharmacological method for inducing gains in skeletal muscle mass, termed hypertrophy. These gains are often highly variable between individuals but have been cited as occurring at a rate of ~0.1% per day up to a certain point ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "9788130803227", "author" : [ { "dropping-particle" : "", "family" : "Hamilton", "given" : "D Lee", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Mackenzie", "given" : "Matthew G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baar", "given" : "Keith R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2009" ] ] }, "number-of-pages" : "45-93", "title" : "Molecular mechanisms of skeletal muscle hypertrophy", "type" : "book", "volume" : "661" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[9]", "plainTextFormattedCitation" : "[9]", "previouslyFormattedCitation" : "[9]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[9]. The definition of RE is the purposeful, repeated movement of a resistance (load) to muscular contraction that is greater than what would be observed in activities of daily living ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Folland", "given" : "Jonathan P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Williams", "given" : "Alun G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Sports Medicine", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2007" ] ] }, "page" : "145-168", "title" : "The Adaptations to Strength Training", "type" : "article-journal", "volume" : "37" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[10]", "plainTextFormattedCitation" : "[10]", "previouslyFormattedCitation" : "[10]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[10]. The goals of chronic resistance exercise, resistance training (RT), often involve the manipulations of: (i) load per repetition (often called intensity), which is most often prescribed as a percentage of single best lift or one repetition maximal strength (1RM); (ii) number of sets performed; (iii) recovery between sets; (iv) muscle action (concentric vs. eccentric); and (v) total exercise volume (i.e., load × repetitions). The effects of differing regimes of RT on strength and muscular hypertrophy were first documented in 1945 by Thomas Delorme who examined the impact of RT to restore strength and power in atrophied muscles following injuries in soldiers ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Delorme", "given" : "Thomas L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Bone & Joint Surgery", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "1945" ] ] }, "page" : "645-667", "title" : "Restoration of muscle power by heavy-resistance exercises", "type" : "article-journal", "volume" : "27" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[11]", "plainTextFormattedCitation" : "[11]", "previouslyFormattedCitation" : "[11]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[11]. These guidelines were then investigated in poliomyelitic patients to determine the response of the quadriceps femoris to chronic RE ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Delorme", "given" : "Thomas L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Schwab", "given" : "Robert S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Watkins", "given" : "Arthur L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Bone & Joint Surgery", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "1948" ] ] }, "page" : "834-847", "title" : "The response of the quadriceps femoris to progressive resistance exercises in poliomyelitic patients", "type" : "article-journal", "volume" : "30" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[8]", "plainTextFormattedCitation" : "[8]", "previouslyFormattedCitation" : "[8]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[8]. Interestingly, it was shown that following approximately four months of progressive RT, there was a significant increase in muscular strength and thigh circumference ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Delorme", "given" : "Thomas L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Schwab", "given" : "Robert S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Watkins", "given" : "Arthur L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Bone & Joint Surgery", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "1948" ] ] }, "page" : "834-847", "title" : "The response of the quadriceps femoris to progressive resistance exercises in poliomyelitic patients", "type" : "article-journal", "volume" : "30" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[8]", "plainTextFormattedCitation" : "[8]", "previouslyFormattedCitation" : "[8]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[8]. These initial investigations preceded an array of studies attempting to elucidate the mechanisms by which RT increases human muscle size and strength. Despite this large body of work, a definitive RE program that is ‘optimal’ in inducing skeletal muscle hypertrophy has yet to be determined. Moreover, we remain largely ignorant as to the biology underpinning skeletal muscle hypertrophy in response to RE, especially in experienced RT athletes. As such, it is the aim of this chapter to synthesize an understanding of the literature relating to RT-induced skeletal muscle hypertrophy. For the purposes of concision and relevance to the human model, an in depth discussion of the molecular regulation of muscle mass will not be undertaken, nor will there be a focus on animal model-derived data; however, in the absence of experimental human data, animal research studies are cited to substantiate discussion points. IINeural Adaptions to RE trainingNeural adaptations to RT generally involve changes in muscle fibre/motor unit coordination, and central ‘learning’ that occur to facilitate increased motor unit recruitment, improved coordinated activation of motor units, and/or reduced antagonist muscle activation ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Folland", "given" : "Jonathan P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Williams", "given" : "Alun G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Sports Medicine", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2007" ] ] }, "page" : "145-168", "title" : "The Adaptations to Strength Training", "type" : "article-journal", "volume" : "37" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[10]", "plainTextFormattedCitation" : "[10]", "previouslyFormattedCitation" : "[10]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[10]. An increase in force production as a result of chronic loading is a hallmark phenotypic adaptation of skeletal muscle to chronic RE. Despite the correlation between muscle cross sectional area (CSA) and strength ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "abstract" : "To determine the effects of dexamethasone treatment on selected components of insulin signaling and glucose metabolism in skeletal muscle obtained from horses before and after administration of a euglycemic-hyperinsulinemic clamp (EHC).", "author" : [ { "dropping-particle" : "", "family" : "Maughan", "given" : "R.J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Watson", "given" : "Jennifer S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Weir", "given" : "J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Physiology", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "1983" ] ] }, "page" : "37-49", "title" : "Strength and cross-sectional area of human skeletal muscle", "type" : "article-journal", "volume" : "338" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[12]", "plainTextFormattedCitation" : "[12]", "previouslyFormattedCitation" : "[12]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[12], it is clear that increases in muscle strength precede measurable changes in indices of skeletal muscle hypertrophy by ~3-4 weeks in na?ve RT participants ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00789.2006", "ISBN" : "8750-7587 (Print)", "ISSN" : "8750-7587", "PMID" : "17053104", "abstract" : "The onset of whole muscle hypertrophy in response to overloading is poorly documented. The purpose of this study was to assess the early changes in muscle size and architecture during a 35-day high-intensity resistance training (RT) program. Seven young healthy volunteers performed bilateral leg extension three times per week on a gravity-independent flywheel ergometer. Cross-sectional area (CSA) in the central (C) and distal (D) regions of the quadriceps femoris (QF), muscle architecture, maximal voluntary contraction (MVC), and electromyographic (EMG) activity were measured before and after 10, 20, and 35 days of RT. By the end of the training period, MVC and EMG activity increased by 38.9 +/- 5.7 and 34.8% +/- 4.7%, respectively. Significant increase in QF CSA (3.5 and 5.2% in the C and D regions, respectively) was observed after 20 days of training, along with a 2.4 +/- 0.7% increase in fascicle length from the 10th day of training. By the end of the 35-day training period, the total increase in QF CSA for regions C and D was 6.5 +/- 1.1 and 7.4 +/- 0.8%, respectively, and fascicle length and pennation angle increased by 9.9 +/- 1.2 and 7.7 +/- 1.3%, respectively. The results show for the first time that changes in muscle size are detectable after only 3 wk of RT and that remodeling of muscle architecture precedes gains in muscle CSA. Muscle hypertrophy seems to contribute to strength gains earlier than previously reported; flywheel training seems particularly effective for inducing these early structural adaptations.", "author" : [ { "dropping-particle" : "", "family" : "Seynnes", "given" : "O R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Boer", "given" : "M", "non-dropping-particle" : "de", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "V", "family" : "Narici", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of applied physiology (Bethesda, Md. : 1985)", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2007" ] ] }, "page" : "368-373", "title" : "Early skeletal muscle hypertrophy and architectural changes in response to high-intensity resistance training.", "type" : "article-journal", "volume" : "102" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Moritani", "given" : "T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "DeVries", "given" : "Herbert A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American Journal of Physical Medicine", "id" : "ITEM-2", "issue" : "3", "issued" : { "date-parts" : [ [ "1979" ] ] }, "page" : "115-130", "title" : "Neural factors versus hypertrophy in the time course of muscle strength gain", "type" : "article-journal", "volume" : "58" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[13,14]", "plainTextFormattedCitation" : "[13,14]", "previouslyFormattedCitation" : "[13,14]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[13,14]. Following 3 weeks of training, however, it appears to be predominantly hypertrophy of the skeletal muscle fibers and an increase in cross-sectional area of the muscle that contribute to maximal developments in strength ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Moritani", "given" : "T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "DeVries", "given" : "Herbert A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American Journal of Physical Medicine", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "1979" ] ] }, "page" : "115-130", "title" : "Neural factors versus hypertrophy in the time course of muscle strength gain", "type" : "article-journal", "volume" : "58" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[14]", "plainTextFormattedCitation" : "[14]", "previouslyFormattedCitation" : "[14]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[14]. The ability to increase strength despite ‘maximal’ neural adaptation is of substantial importance for several populations but especially those who chronically perform RE. For example, Judge and colleagues examined sport-specific knee strengthening exercises in elite athletes to determine if maximal voluntary contraction (MVC) of the quadriceps could be increased with chronic RE ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1080/0264041031000071173", "ISBN" : "0264-0414 (Print)\\r0264-0414 (Linking)", "ISSN" : "0264-0414", "PMID" : "12800864", "abstract" : "The aim of this study was to assess the effects of variations in the volume and intensity of resistance training in highly skilled athletes on neural adaptive mechanisms: the maximality and pattern of neural drive. The maximality of muscle activation was measured using a high-resolution sample and hold amplifier to record interpolated twitches. The pattern of neural drive was measured by analysing isometric torque-time curves and electromyographic (EMG) characteristics during the performance of rapid isometric contractions at maximal effort. The volume and intensity of training were varied at 4-weekly intervals to systematically emphasize the development of strength, power and motor performance in 14 highly skilled track and field athletes (e.g. discus, hammer, javelin, shot put and weight). Knee extension strength increased significantly by 15% during steady maximal isometric contractions and by 24% during rapid isometric contractions at maximal effort after the 16-week training programme (P < 0.05). Increases in EMG amplitude and rate of EMG activation indicated that improvements to the pattern of neural drive occurred with sport-specific resistance training (P < 0.05). The maximality and pattern of neural drive did not change in the control group.", "author" : [ { "dropping-particle" : "", "family" : "Judge", "given" : "Larry W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moreau", "given" : "Chad", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burke", "given" : "Jeanmarie R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of sports sciences", "id" : "ITEM-1", "issue" : "March 2015", "issued" : { "date-parts" : [ [ "2003" ] ] }, "page" : "419-427", "title" : "Neural adaptations with sport-specific resistance training in highly skilled athletes.", "type" : "article-journal", "volume" : "21" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[15]", "plainTextFormattedCitation" : "[15]", "previouslyFormattedCitation" : "[15]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[15]. They found that individuals who performed the RT intervention had a 10% increase in MVC despite no change in central (voluntary) activation of the quadriceps muscle ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1080/0264041031000071173", "ISBN" : "0264-0414 (Print)\\r0264-0414 (Linking)", "ISSN" : "0264-0414", "PMID" : "12800864", "abstract" : "The aim of this study was to assess the effects of variations in the volume and intensity of resistance training in highly skilled athletes on neural adaptive mechanisms: the maximality and pattern of neural drive. The maximality of muscle activation was measured using a high-resolution sample and hold amplifier to record interpolated twitches. The pattern of neural drive was measured by analysing isometric torque-time curves and electromyographic (EMG) characteristics during the performance of rapid isometric contractions at maximal effort. The volume and intensity of training were varied at 4-weekly intervals to systematically emphasize the development of strength, power and motor performance in 14 highly skilled track and field athletes (e.g. discus, hammer, javelin, shot put and weight). Knee extension strength increased significantly by 15% during steady maximal isometric contractions and by 24% during rapid isometric contractions at maximal effort after the 16-week training programme (P < 0.05). Increases in EMG amplitude and rate of EMG activation indicated that improvements to the pattern of neural drive occurred with sport-specific resistance training (P < 0.05). The maximality and pattern of neural drive did not change in the control group.", "author" : [ { "dropping-particle" : "", "family" : "Judge", "given" : "Larry W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moreau", "given" : "Chad", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burke", "given" : "Jeanmarie R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of sports sciences", "id" : "ITEM-1", "issue" : "March 2015", "issued" : { "date-parts" : [ [ "2003" ] ] }, "page" : "419-427", "title" : "Neural adaptations with sport-specific resistance training in highly skilled athletes.", "type" : "article-journal", "volume" : "21" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[15]", "plainTextFormattedCitation" : "[15]", "previouslyFormattedCitation" : "[15]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[15]. The absence of an increase in neural activation with RT in a previously trained population is in agreement with the findings of H?kkinen et al. ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "8750-7587 (Print)\\r0161-7567 (Linking)", "ISSN" : "8750-7587", "PMID" : "3215840", "abstract" : "Neuromuscular and hormonal adaptations to prolonged strength training were investigated in nine elite weight lifters. The average increases occurred over the 2-yr follow-up period in the maximal neural activation (integrated electromyogram, IEMG; 4.2%, P = NS), maximal isometric leg-extension force (4.9%, P = NS), averaged concentric power index (4.1%, P = NS), total weight-lifting result (2.8%, P less than 0.05), and total mean fiber area (5.9%, P = NS) of the vastus lateralis muscle, respectively. The training period resulted in increases in the concentrations of serum testosterone from 19.8 +/- 5.3 to 25.1 +/- 5.2 nmol/l (P less than 0.05), luteinizing hormone (LH) from 8.6 +/- 0.8 to 9.1 +/- 0.8 U/l (P less than 0.05), follicle-stimulating hormone (FSH) from 4.2 +/- 2.0 to 5.3 +/- 2.3 U/l (P less than 0.01), and testosterone-to-serum sex hormone-binding globulin (SHBG) ratio (P less than 0.05). The annual mean value of the second follow-up year for the serum testosterone-to-SHBG ratio correlated significantly (r = 0.84, P less than 0.01) with the individual changes during the 2nd yr in the averaged concentric power. The present results suggest that prolonged intensive strength training in elite athletes may influence the pituitary and possibly hypothalamic levels, leading to increased serum levels of testosterone. This may create more optimal conditions to utilize more intensive training leading to increased strength development.", "author" : [ { "dropping-particle" : "", "family" : "H\u00e4kkinen", "given" : "K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pakarinen", "given" : "a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Alen", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kauhanen", "given" : "H", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "V", "family" : "Komi", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of applied physiology (Bethesda, Md. : 1985)", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1988" ] ] }, "page" : "2406-2412", "title" : "Neuromuscular and hormonal adaptations in athletes to strength training in two years.", "type" : "article-journal", "volume" : "65" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[16]", "plainTextFormattedCitation" : "[16]", "previouslyFormattedCitation" : "[16]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[16]. In studying elite weight lifters, these authors noted an increase in maximal Olympic-style lifting of ~7.5 kg following training over a 2 year span with no measurable change in muscle fiber cross-sectional area ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "8750-7587 (Print)\\r0161-7567 (Linking)", "ISSN" : "8750-7587", "PMID" : "3215840", "abstract" : "Neuromuscular and hormonal adaptations to prolonged strength training were investigated in nine elite weight lifters. The average increases occurred over the 2-yr follow-up period in the maximal neural activation (integrated electromyogram, IEMG; 4.2%, P = NS), maximal isometric leg-extension force (4.9%, P = NS), averaged concentric power index (4.1%, P = NS), total weight-lifting result (2.8%, P less than 0.05), and total mean fiber area (5.9%, P = NS) of the vastus lateralis muscle, respectively. The training period resulted in increases in the concentrations of serum testosterone from 19.8 +/- 5.3 to 25.1 +/- 5.2 nmol/l (P less than 0.05), luteinizing hormone (LH) from 8.6 +/- 0.8 to 9.1 +/- 0.8 U/l (P less than 0.05), follicle-stimulating hormone (FSH) from 4.2 +/- 2.0 to 5.3 +/- 2.3 U/l (P less than 0.01), and testosterone-to-serum sex hormone-binding globulin (SHBG) ratio (P less than 0.05). The annual mean value of the second follow-up year for the serum testosterone-to-SHBG ratio correlated significantly (r = 0.84, P less than 0.01) with the individual changes during the 2nd yr in the averaged concentric power. The present results suggest that prolonged intensive strength training in elite athletes may influence the pituitary and possibly hypothalamic levels, leading to increased serum levels of testosterone. This may create more optimal conditions to utilize more intensive training leading to increased strength development.", "author" : [ { "dropping-particle" : "", "family" : "H\u00e4kkinen", "given" : "K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pakarinen", "given" : "a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Alen", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kauhanen", "given" : "H", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "V", "family" : "Komi", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of applied physiology (Bethesda, Md. : 1985)", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1988" ] ] }, "page" : "2406-2412", "title" : "Neuromuscular and hormonal adaptations in athletes to strength training in two years.", "type" : "article-journal", "volume" : "65" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[16]", "plainTextFormattedCitation" : "[16]", "previouslyFormattedCitation" : "[16]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[16]. These studies provide evidence that despite training status or the achievement of ‘full’ neural recruitment, the potential still exists for further increases in strength above what is thought to be maximal. Past examinations of alterations in motor unit recruitment have yielded variable findings. The integrated electromyographical (iEMG) signal (muscle fibre activation) has been widely accepted as the common measurement to assess neural activity within skeletal muscle. As the bulk electrical signal that represents the sum of electrical contributions made by active motor units, iEMG is usually measured by electrodes placed on the skin above the activated muscle and is often used to determine if a muscle activation is increased following a training stimulus ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.01070.2003", "ISBN" : "8750-7587 (Print) 0161-7567 (Linking)", "ISSN" : "8750-7587", "PMID" : "15016793", "abstract" : "This brief review examines some of the methods used to infer central control strategies from surface electromyogram (EMG) recordings. Among the many uses of the surface EMG in studying the neural control of movement, the review critically evaluates only some of the applications. The focus is on the relations between global features of the surface EMG and the underlying physiological processes. Because direct measurements of motor unit activation are not available and many factors can influence the signal, these relations are frequently misinterpreted. These errors are compounded by the counterintuitive effects that some system parameters can have on the EMG signal. The phenomenon of crosstalk is used as an example of these problems. The review describes the limitations of techniques used to infer the level of muscle activation, the type of motor unit recruited, the upper limit of motor unit recruitment, the average discharge rate, and the degree of synchronization between motor units. Although the global surface EMG is a useful measure of muscle activation and assessment, there are limits to the information that can be extracted from this signal.", "author" : [ { "dropping-particle" : "", "family" : "Farina", "given" : "Dario", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Merletti", "given" : "Roberto", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Enoka", "given" : "Roger M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of applied physiology (Bethesda, Md. : 1985)", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2004" ] ] }, "page" : "1486-1495", "title" : "The extraction of neural strategies from the surface EMG.", "type" : "article-journal", "volume" : "96" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[17]", "plainTextFormattedCitation" : "[17]", "previouslyFormattedCitation" : "[17]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[17]. Using iEMG, Narici and colleagues observed the effects of strength training using an isokinetic movement on a dynamometer on quadriceps muscle activation over 60 days in untrained males ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/BF02388334", "ISBN" : "1439-6327", "ISSN" : "03015548", "PMID" : "2583179", "abstract" : "Four male subjects aged 23-34 years were studied during 60 days of unilateral strength training and 40 days of detraining. Training was carried out four times a week and consisted of six series of ten maximal isokinetic knee extensions at an angular velocity of 2.09 rad.s-1. At the start and at every 20th day of training and detraining, isometric maximal voluntary contraction (MVC), integrated electromyographic activity (iEMG) and quadriceps muscle cross-sectional area (CSA) assessed at seven fractions of femur length (Lf), by nuclear magnetic resonance imaging, were measured on both trained (T) and untrained (UT) legs. Isokinetic torques at 30 degrees before full knee extension were measured before and at the end of training at: 0, 1.05, 2.09, 3.14, 4.19, 5.24 rad.s-1. After 60 days T leg CSA had increased by 8.5% +/- 1.4% (mean +/- SEM, n = 4, p less than 0.001), iEMG by 42.4% +/- 16.5% (p less than 0.01) and MVC by 20.8% +/- 5.4% (p less than 0.01). Changes during detraining had a similar time course to those of training. No changes in UT leg CSA were observed while iEMG and MVC increased by 24.8% +/- 10% (N.S.) and 8.7% +/- 4.3% (N.S.), respectively. The increase in quadriceps muscle CSA was maximal at 2/10 Lf (12.0% +/- 1.5%, p less than 0.01) and minimal, proximally to the knee, at 8/10 Lf (3.5% +/- 1.2%, N.S.). Preferential hypertrophy of the vastus medialis and intermedius muscles compared to those of the rectus femoris and lateralis muscles was observed.", "author" : [ { "dropping-particle" : "V.", "family" : "Narici", "given" : "M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Roi", "given" : "G. S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Landoni", "given" : "L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Minetti", "given" : "a. E.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cerretelli", "given" : "P.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European Journal of Applied Physiology and Occupational Physiology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1989" ] ] }, "page" : "310-319", "title" : "Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps", "type" : "article-journal", "volume" : "59" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[18]", "plainTextFormattedCitation" : "[18]", "previouslyFormattedCitation" : "[18]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[18]. Participants performed six sets of ten isokinetic knee extensions 4 times per week on one leg only. Training resulted in a significant increase (~42%) in the iEMG signal in the trained leg and, despite remaining untrained, they also observed a non-significant increase in iEMG of 25% in the untrained leg ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/BF02388334", "ISBN" : "1439-6327", "ISSN" : "03015548", "PMID" : "2583179", "abstract" : "Four male subjects aged 23-34 years were studied during 60 days of unilateral strength training and 40 days of detraining. Training was carried out four times a week and consisted of six series of ten maximal isokinetic knee extensions at an angular velocity of 2.09 rad.s-1. At the start and at every 20th day of training and detraining, isometric maximal voluntary contraction (MVC), integrated electromyographic activity (iEMG) and quadriceps muscle cross-sectional area (CSA) assessed at seven fractions of femur length (Lf), by nuclear magnetic resonance imaging, were measured on both trained (T) and untrained (UT) legs. Isokinetic torques at 30 degrees before full knee extension were measured before and at the end of training at: 0, 1.05, 2.09, 3.14, 4.19, 5.24 rad.s-1. After 60 days T leg CSA had increased by 8.5% +/- 1.4% (mean +/- SEM, n = 4, p less than 0.001), iEMG by 42.4% +/- 16.5% (p less than 0.01) and MVC by 20.8% +/- 5.4% (p less than 0.01). Changes during detraining had a similar time course to those of training. No changes in UT leg CSA were observed while iEMG and MVC increased by 24.8% +/- 10% (N.S.) and 8.7% +/- 4.3% (N.S.), respectively. The increase in quadriceps muscle CSA was maximal at 2/10 Lf (12.0% +/- 1.5%, p less than 0.01) and minimal, proximally to the knee, at 8/10 Lf (3.5% +/- 1.2%, N.S.). Preferential hypertrophy of the vastus medialis and intermedius muscles compared to those of the rectus femoris and lateralis muscles was observed.", "author" : [ { "dropping-particle" : "V.", "family" : "Narici", "given" : "M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Roi", "given" : "G. S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Landoni", "given" : "L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Minetti", "given" : "a. E.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cerretelli", "given" : "P.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European Journal of Applied Physiology and Occupational Physiology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1989" ] ] }, "page" : "310-319", "title" : "Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps", "type" : "article-journal", "volume" : "59" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[18]", "plainTextFormattedCitation" : "[18]", "previouslyFormattedCitation" : "[18]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[18]. These findings suggest that studies implementing a unilateral RT design as a within-subject control would have to be aware of cross-adaptation to the untrained limb ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/BF02388334", "ISBN" : "1439-6327", "ISSN" : "03015548", "PMID" : "2583179", "abstract" : "Four male subjects aged 23-34 years were studied during 60 days of unilateral strength training and 40 days of detraining. Training was carried out four times a week and consisted of six series of ten maximal isokinetic knee extensions at an angular velocity of 2.09 rad.s-1. At the start and at every 20th day of training and detraining, isometric maximal voluntary contraction (MVC), integrated electromyographic activity (iEMG) and quadriceps muscle cross-sectional area (CSA) assessed at seven fractions of femur length (Lf), by nuclear magnetic resonance imaging, were measured on both trained (T) and untrained (UT) legs. Isokinetic torques at 30 degrees before full knee extension were measured before and at the end of training at: 0, 1.05, 2.09, 3.14, 4.19, 5.24 rad.s-1. After 60 days T leg CSA had increased by 8.5% +/- 1.4% (mean +/- SEM, n = 4, p less than 0.001), iEMG by 42.4% +/- 16.5% (p less than 0.01) and MVC by 20.8% +/- 5.4% (p less than 0.01). Changes during detraining had a similar time course to those of training. No changes in UT leg CSA were observed while iEMG and MVC increased by 24.8% +/- 10% (N.S.) and 8.7% +/- 4.3% (N.S.), respectively. The increase in quadriceps muscle CSA was maximal at 2/10 Lf (12.0% +/- 1.5%, p less than 0.01) and minimal, proximally to the knee, at 8/10 Lf (3.5% +/- 1.2%, N.S.). Preferential hypertrophy of the vastus medialis and intermedius muscles compared to those of the rectus femoris and lateralis muscles was observed.", "author" : [ { "dropping-particle" : "V.", "family" : "Narici", "given" : "M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Roi", "given" : "G. S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Landoni", "given" : "L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Minetti", "given" : "a. E.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cerretelli", "given" : "P.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European Journal of Applied Physiology and Occupational Physiology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1989" ] ] }, "page" : "310-319", "title" : "Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps", "type" : "article-journal", "volume" : "59" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[18]", "plainTextFormattedCitation" : "[18]", "previouslyFormattedCitation" : "[18]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[18]. There are inherent issues in using surface EMG analysis across time in a longitudinal manner, however, such as electrode placement and replacement, changes in impedance (thickness) of the skin/fat, and changes in muscle morphology that could cause variability in the repeatability and reliability of these measurements with chronic RE ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1016/S1388-2457(98)00050-9", "ISBN" : "1388-2457", "ISSN" : "13882457", "PMID" : "10378745", "abstract" : "Objectives: The aim of the study was to investigate short-term, intermediate-term and long-term reliability of surface electromyographic (EMG) measurements. Methods: Eighteen healthy subjects performed 810 isometric knee extension tests. Reliability for maximum voluntary contraction (MVC) and 50% MVC was assessed with retest intervals of 3 min, 90 min and 6 weeks. Reliability for sustained contractions was assessed with retest intervals of 90 min and 6 weeks. EMG was recorded from the rectus femoris, vastus lateralis and vastus medialis muscles. The root mean square (RMS) and the median frequency (MF) parameters were extracted. At sustained contraction tasks, estimated linear regression values of both parameters were analyzed. Bland-Altman-plots, coefficient of repeatability, Pearson's coefficient of correlation and intra class correlation (ICC) procedures were applied to assess test-retest reliability. Results: EMG recordings taken at short-term intervals were generally better reproducible than those of the longer-term intervals. Moreover, 50% MVC EMG recordings demonstrated better reproducibility than 100% MVC measurements, and EMG recorded from the rectus femoris were more constant than that from the vastus lateralis or vastus medialis. The MF parameter recorded from the rectus femoris was the only reliable parameter of EMG fatigue change. Conclusion: In our set up, EMG measurement is best suited for clinical applications if submaximal MVC measurements are performed and signal is taken from rectus femoris muscle.", "author" : [ { "dropping-particle" : "", "family" : "Kollmitzer", "given" : "Josef", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ebenbichler", "given" : "Gerold R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kopf", "given" : "Andreas", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Clinical Neurophysiology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1999" ] ] }, "page" : "725-734", "title" : "Reliability of surface electromyographic measurements", "type" : "article-journal", "volume" : "110" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1016/0013-4694(88)90169-1", "ISBN" : "00134649 (ISSN)", "ISSN" : "00134694", "PMID" : "2453334", "abstract" : "Surface myoelectric signals were detected from the skin surface above the tibialis anterior muscle, the peroneus brevis muscle, the soleus muscle and the tibial bone during selective maximal electrical stimulation of the tibialis anterior muscle in 12 normal subjects. The double differential technique developed by Broman et al. (1985) was used to determine if the detected signal was due to volume conduction from the tibialis anterior fibers. The peak-to-peak (PP), average rectified (ARV) and root mean square (RMS) amplitudes of the M waves were computed for each detection location. The values detected on the tibial bone, on the peroneus and on the soleus muscles were normalized with respect to those detected on the tibialis anterior and ranged from 4.8% to 33.0% (PP), 4.7% to 36.0% (ARV), and 7.7% to 37.4% (RMS) for the tibial bone area; from 4.0% to 20.0% (PP), 3.5% to 10.0% (ARV), and 3.0% to 10.0% (RMS) for the peroneus brevis muscle area; and from 3.0% to 8.0% (PP), 3.4% to 9.1% (ARV), and 2.0% to 9.8% (RMS) for the soleus muscle area. Neither peak-to-peak values, average rectified values nor root mean square values appeared to be correlated with leg size. It is concluded that a surface myoelectric signal detected on the skin above a leg muscle and having a peak-to-peak amplitude of up to 16.6% of a signal detected above a neighboring muscle may be due to cross-talk rather than to activation of the muscle below the electrode.", "author" : [ { "dropping-particle" : "", "family" : "Luca", "given" : "C J", "non-dropping-particle" : "De", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Merletti", "given" : "R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Electroencephalography and clinical neurophysiology", "id" : "ITEM-2", "issued" : { "date-parts" : [ [ "1988" ] ] }, "page" : "568-575", "title" : "Surface myoelectric signal cross-talk among muscles of the leg.", "type" : "article-journal", "volume" : "69" }, "uris" : [ "" ] }, { "id" : "ITEM-3", "itemData" : { "DOI" : "10.1002/mus.10256", "ISBN" : "0148-639X (Print)\\n0148-639X (Linking)", "ISSN" : "0148-639X", "PMID" : "12402291", "abstract" : "Surface electromyographic (EMG) crosstalk between vastus lateralis, vastus medialis, and rectus femoris muscles was evaluated by selective electrical stimulation of one muscle and recording from the stimulated and another muscle with linear surface arrays of eight electrodes. The ratio between the amplitude of the signals recorded over nonstimulated and stimulated muscles and their correlation coefficient were used as indices to quantify crosstalk. Single-differential and double-differential detection systems were used with interelectrode distances in the range 10-40 mm. The multichannel EMG signals clearly showed that crosstalk is largely due to nonpropagating potentials that correspond in time to the end of the propagation of the action potentials generated by the stimulated muscle. The crosstalk signal increased with increasing interelectrode distance and was statistically higher for single- than for double-differential recordings. The correlation-based indices of crosstalk were poorly correlated with the amplitude-based indices. Moreover, the characteristic spectral frequencies of the signals detected over the nonstimulated muscles were statistically higher than those from the stimulated muscles. A mathematical model of signal generation was used to explain the experimental findings. This study clarifies many controversial findings of past investigations and creates the basis for crosstalk interpretation, simulation, and reduction.", "author" : [ { "dropping-particle" : "", "family" : "Farina", "given" : "Dario", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Merletti", "given" : "Roberto", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Indino", "given" : "Barbara", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Nazzaro", "given" : "Marisa", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pozzo", "given" : "Marco", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Muscle & nerve", "id" : "ITEM-3", "issue" : "November", "issued" : { "date-parts" : [ [ "2002" ] ] }, "page" : "681-695", "title" : "Surface EMG crosstalk between knee extensor muscles: experimental and model results.", "type" : "article-journal", "volume" : "26" }, "uris" : [ "" ] }, { "id" : "ITEM-4", "itemData" : { "DOI" : "10.1016/S1050-6411(03)00040-3", "ISBN" : "10506411", "ISSN" : "10506411", "abstract" : "This paper focuses on methodological issues related to surface electromyographic (EMG) signal detection from the low back muscles. In particular, we analysed (1) the characteristics (in terms of propagating components) of the signals detected from these muscles; (2) the effect of electrode location on the variables extracted from surface EMG; (3) the effect of the inter-electrode distance (IED) on the same variables; (4) the possibility of assessing fatigue during high and very low force level contractions. To address these issues, we detected single differential surface EMG signals by arrays of eight electrodes from six locations on the two sides of the spine, at the levels of the first (L1), the second (L2), and the fifth (L5) lumbar vertebra. In total, 42 surface EMG channels were acquired at the same time during both high and low force, short and long duration contractions. The main results were: (1) signal quality is poor with predominance of non-travelling components; (2) as a consequence of point (1), in the majority of the cases it is not possible to reliably estimate muscle fiber conduction velocity; (3) despite the poor signal quality, it was possible to distinguish the fatigue properties of the investigated muscles and the fatigability at different contraction levels; (4) IED affects the sensitivity of surface EMG variables to electrode location and large IEDs are suggested when spectral and amplitude analysis is performed; (5) the sensitivity of surface EMG variables to changes in electrode location is on average larger than for other muscles with less complex architecture; (6) IED influences amplitude initial values and slopes, and spectral variable initial values; (7) normalized slopes for both amplitude and spectral variables are not affected by IED and, thus, are suggested for fatigue analysis at different postures or during movement, when IED may change in different conditions (in case of separated electrodes); (8) the surface EMG technique at the global level of amplitude and spectral analysis cannot be used to characterize fatigue properties of low back muscles during very low level, long duration contractions since in these cases the non-stable MU pool has a major influence on the EMG variables. These considerations clarify issues only partially investigated in past studies. The limitations indicated above are important and should be carefully discussed when presenting surface EMG results as a means for low back muscle assessment in \u2026", "author" : [ { "dropping-particle" : "", "family" : "Farina", "given" : "Dario", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Gazzoni", "given" : "Marco", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Merletti", "given" : "Roberto", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Electromyography and Kinesiology", "id" : "ITEM-4", "issued" : { "date-parts" : [ [ "2003" ] ] }, "page" : "319-332", "title" : "Assessment of low back muscle fatigue by surface EMG signal analysis: methodological aspects", "type" : "article-journal", "volume" : "13" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[19\u201322]", "plainTextFormattedCitation" : "[19\u201322]", "previouslyFormattedCitation" : "[19\u201322]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[19–22]. Furthermore, contradictory evidence exists as to whether maximum activation of the motor units innervating fibres of a given muscle are increased as a result of RT ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1080/00140137208924444", "ISSN" : "0014-0139", "author" : [ { "dropping-particle" : "V", "family" : "Komi", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Buskirk", "given" : "E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Ergonomics", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "1972", "7", "1" ] ] }, "note" : "doi: 10.1080/00140137208924444", "page" : "417-434", "publisher" : "Taylor & Francis", "title" : "Effect of Eccentric and Concentric Muscle Conditioning on Tension and Electrical Activity of Human Muscle", "type" : "article-journal", "volume" : "15" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Thorstensson", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Karlsson", "given" : "J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Viitasalo", "given" : "J H T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Komi", "given" : "P V E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Acta Physiologica Scandinavica", "id" : "ITEM-2", "issue" : "2", "issued" : { "date-parts" : [ [ "1976" ] ] }, "page" : "232-236", "title" : "Effect of Strength Training on EMG of Human Skeletal Muscle", "type" : "article-journal", "volume" : "98" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[23,24]", "plainTextFormattedCitation" : "[23,24]", "previouslyFormattedCitation" : "[23,24]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[23,24]. In summary, changes in neural activation of skeletal muscle fibres are seen early with RT and have an impact on strength gains seen in the initial weeks of beginning RE and are a greater contributor to strength gains in untrained persons; however, increases in muscle mass/muscle fibre CSA drive the increases in strength in the latter phases of most RT programs.IIIProtein Synthesis and HypertrophyIII.iProtein Synthesis and Resistance ExerciseChanges in skeletal muscle size are underpinned, in part, by the feeding-driven changes in muscle protein synthesis (MPS) and muscle protein breakdown (MPB). Increases in muscle fibre cross-sectional area due to RT occur when aggregate rates of MPS exceed those of MPB ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s40279-014-0152-3", "ISBN" : "4027901401", "ISSN" : "0112-1642", "author" : [ { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Sports Medicine", "id" : "ITEM-1", "issue" : "S1", "issued" : { "date-parts" : [ [ "2014", "5", "3" ] ] }, "page" : "71-77", "title" : "A Brief Review of Critical Processes in Exercise-Induced Muscular Hypertrophy", "type" : "article-journal", "volume" : "44" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[25]", "plainTextFormattedCitation" : "[25]", "previouslyFormattedCitation" : "[25]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[25]. In the post-absorptive state, MPB exceeds MPS resulting in a state of net catabolism. With provision of amino acids (protein ingestion), MPS is stimulated and MPB is reduced such that MPS is greater than MPB resulting in net protein accretion ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1017/S0007114512002516", "ISBN" : "1111111111", "ISSN" : "0007-1145", "PMID" : "23107527", "abstract" : "Dietary guidelines from a variety of sources are generally congruent that an adequate dietary protein intake for persons over the age of 19 is between 0\u00b78-0\u00b79 g protein/kg body weight/d. According to the US/Canadian Dietary Reference Intakes, the RDA for protein of 0\u00b78 g protein/kg/d is \"...the average daily intake level that is sufficient to meet the nutrient requirement of nearly all [~98 %]\u2026 healthy individuals...\" The panel also states that \"...no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise.\" These recommendations are in contrast to recommendations from the US and Canadian Dietetic Association: \"Protein recommendations for endurance and strength trained athletes range from 1\u00b72 to 1\u00b77 g/kg/d.\" The disparity between those setting dietary protein requirements and those who might be considered to be making practical recommendations for athletes is substantial. This may reflect a situation where an adaptive advantage of protein intakes higher than recommended protein requirements exists. That population protein requirements are still based on nitrogen balance may also be a point of contention since achieving balanced nitrogen intake and excretion likely means little to an athlete who has the primary goal of exercise performance. The goal of the present review is to critically analyse evidence from both acute and chronic dietary protein-based studies in which athletic performance, or correlates thereof, have been measured. An attempt will be made to distinguish between protein requirements set by data from nitrogen balance studies, and a potential adaptive 'advantage' for athletes of dietary protein in excess of the RDA.", "author" : [ { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "British Journal of Nutrition", "id" : "ITEM-1", "issue" : "S2", "issued" : { "date-parts" : [ [ "2012" ] ] }, "page" : "S158-S167", "title" : "Dietary protein requirements and adaptive advantages in athletes", "type" : "article-journal", "volume" : "108" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "1743-7075-9-40 [pii] 10.1186/1743-7075-9-40", "ISBN" : "1743-7075 (Electronic) 1743-7075 (Linking)", "PMID" : "22594765", "abstract" : "Provision of dietary amino acids increases skeletal muscle protein synthesis (MPS), an effect that is enhanced by prior resistance exercise. As a fundamentally necessary process in the enhancement of muscle mass, strategies to enhance rates of MPS would be beneficial in the development of interventions aimed at increasing skeletal muscle mass particularly when combined with chronic resistance exercise. The purpose of this review article is to provide an update on current findings regarding the nutritional regulation of MPS and highlight nutrition based strategies that may serve to maximize skeletal muscle protein anabolism with resistance exercise. Such factors include timing of protein intake, dietary protein type, the role of leucine as a key anabolic amino acid, and the impact of other macronutrients (i.e. carbohydrate) on the regulation of MPS after resistance exercise. We contend that nutritional strategies that serve to maximally stimulate MPS may be useful in the development of nutrition and exercise based interventions aimed at enhancing skeletal muscle mass which may be of interest to elderly populations and to athletes.", "author" : [ { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "T A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "N A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Research Group", "given" : "E M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Nutr Metab (Lond)", "edition" : "2012/05/19", "id" : "ITEM-2", "issue" : "1", "issued" : { "date-parts" : [ [ "2012" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "40", "title" : "Nutritional regulation of muscle protein synthesis with resistance exercise: strategies to enhance anabolism", "type" : "article-journal", "volume" : "9" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[26,27]", "plainTextFormattedCitation" : "[26,27]", "previouslyFormattedCitation" : "[26,27]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[26,27]. Young healthy men and women who consume adequate daily protein fluctuate between periods of negative and positive protein balance which remain roughly equal throughout a day resulting in the maintenance of muscle mass ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "0002-9513 (Print)\\r0002-9513 (Linking)", "ISSN" : "0002-9513", "PMID" : "7900797", "abstract" : "The rates of protein synthesis and degradation and of amino acid transport were determined in the leg muscle of untrained postabsorptive normal volunteers at rest and approximately 3 h after a resistance exercise routine. The methodology involved use of stable isotopic tracers of amino acids, arteriovenous catheterization of the femoral vessels, and biopsy of the vastus lateralis muscle. During postexercise recovery, the rate of intramuscular phenylalanine utilization for protein synthesis increased above the basal value by 108 +/- 18%, whereas the rate of release from proteolysis increased by 51 +/- 17%. Muscle protein balance improved (P < 0.05) after exercise but did not become positive (from -15 +/- 12 to -6 +/- 3 nmol phenylalanine.min-1.100 ml leg volume-1). After exercise, rates of inward transport of leucine, lysine, and alanine increased (P < 0.05) above the basal state from 132 +/- 16 to 208 +/- 29, from 122 +/- 8 to 260 +/- 8, and from 384 +/- 71 to 602 +/- 89 nmol.min-1.100 ml leg-1, respectively. Transport of phenylalanine did not change significantly. These results indicate that, during recovery after resistance exercise, muscle protein turnover is increased because of an acceleration of synthesis and degradation. A postexercise acceleration of amino acid transport may contribute to the relatively greater stimulation of protein synthesis.", "author" : [ { "dropping-particle" : "", "family" : "Biolo", "given" : "G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Maggi", "given" : "S P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Williams", "given" : "B D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tipton", "given" : "K D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wolfe", "given" : "R R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The American journal of physiology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1995" ] ] }, "page" : "E514-E520", "title" : "Increased rates of muscle protein turnover and amino acid transport after resistance exercise in humans.", "type" : "article-journal", "volume" : "268" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[28]", "plainTextFormattedCitation" : "[28]", "previouslyFormattedCitation" : "[28]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[28]. Changes in the rates of MPS in response to a bout of acute fasted-state RE have been examined with several variations in training stimulus. Phillips and colleagues aimed to determine the changes in MPS associated with an acute RE routine in untrained participants. They found that RE resulted in a significant increase in mixed muscle protein fractional synthetic rate (FSR, the tracer-derived measurement of MPS) above rest in the quadriceps muscle at times 3 hours (112%), 24 hours (65%) and 48 hours (34%) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "0002-9513 (Print) 0002-9513 (Linking)", "ISSN" : "0002-9513", "PMID" : "9252485", "abstract" : "Mixed muscle protein fractional synthesis rate (FSR) and fractional breakdown rate (FBR) were examined after an isolated bout of either concentric or eccentric resistance exercise. Subjects were eight untrained volunteers (4 males, 4 females). Mixed muscle protein FSR and FBR were determined using primed constant infusions of [2H5]phenylalanine and 15N-phenylalanine, respectively. Subjects were studied in the fasted state on four occasions: at rest and 3, 24, and 48 h after a resistance exercise bout. Exercise was eight sets of eight concentric or eccentric repetitions at 80% of each subject's concentric 1 repetition maximum. There was no significant difference between contraction types for either FSR, FBR, or net balance (FSR minus FBR). Exercise resulted in significant increases above rest in muscle FSR at all times: 3 h = 112%, 24 h = 65%, 48 h = 34% (P < 0.01). Muscle FBR was also increased by exercise at 3 h (31%; P < 0.05) and 24 h (18%; P < 0.05) postexercise but returned to resting levels by 48 h. Muscle net balance was significantly increased after exercise at all time points [(in %/h) rest = -0.0573 +/- 0.003 (SE), 3 h = -0.0298 +/- 0.003, 24 h = -0.0413 +/- 0.004, and 48 h = -0.0440 +/- 0.005], and was significantly different from zero at all time points (P < 0.05). There was also a significant correlation between FSR and FBR (r = 0.88, P < 0.001). We conclude that exercise resulted in an increase in muscle net protein balance that persisted for up to 48 h after the exercise bout and was unrelated to the type of muscle contraction performed.", "author" : [ { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tipton", "given" : "K D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aarsland", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wolf", "given" : "S E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wolfe", "given" : "R R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The American journal of physiology", "edition" : "1997/07/01", "id" : "ITEM-1", "issue" : "1 Pt 1", "issued" : { "date-parts" : [ [ "1997", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 2 ( ", "page" : "E99-107", "title" : "Mixed muscle protein synthesis and breakdown after resistance exercise in humans.", "type" : "article-journal", "volume" : "273" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[29]", "plainTextFormattedCitation" : "[29]", "previouslyFormattedCitation" : "[29]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[29]. These data are in agreement with Kim et al. who compared the acute MPS response in a within subject design, where one limb performed chronic RE for 8-weeks while the other did not. In response to an acute bout of RE it was determined that rates of myofibrillar protein MPS were elevated in both the trained (+44%) and untrained limbs (+42%) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2005.093708", "ISSN" : "0022-3751", "PMID" : "16051622", "abstract" : "The purpose of the present investigation was to determine how fasted-state protein synthesis was affected, acutely, by resistance training. Eight men (24.8+/-1.7 years, body mass index=23.2+/-1.0 kg m-2; means+/-s.e.m.) undertook an 8 week programme of unilateral resistance exercise training (3 sessions week-1, progression from two to four sets; intensity was 80% of the subjects' single repetition maximum (1RM): knee extension and leg press). Following training, subjects underwent two primed constant infusions of l-[ring-13C6]phenylalanine to determine mixed and myofibrillar muscle protein synthesis (MPS) at rest and 12 h after an acute bout of resistance exercise at the same exercise intensity--each leg 80% of 1RM. Biopsies (vastus lateralis) were taken to measure incorporation of labelled phenylalanine into mixed and myofibrillar skeletal muscle proteins and yield fractional MPS. Training resulted in significant dynamic strength gains that were greater (P<0.001) in the trained leg. Hypertrophy of type IIa and IIx fibres (P<0.05) was observed following training. After training, resting mixed MPS rate was elevated (+48%; P<0.05). Acutely, resistance exercise stimulated mixed MPS only in the untrained leg (P<0.05). Myofibrillar MPS was unchanged at rest following training (P=0.61). Myofibrillar MPS increased after resistance exercise (P<0.05), but was not different between the trained and untrained legs (P=0.36). We observed divergent changes in resting mixed versus myofibrillar protein synthesis with training. In addition, resistance training modified the acute response of MPS to resistance exercise by dampening the increased synthesis of non-myofibrillar proteins while maintaining the synthesis of myofibrillar proteins.", "author" : [ { "dropping-particle" : "", "family" : "Kim", "given" : "Paul L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-1", "issue" : "Pt 1", "issued" : { "date-parts" : [ [ "2005", "10", "1" ] ] }, "page" : "283-90", "title" : "Fasted-state skeletal muscle protein synthesis after resistance exercise is altered with training.", "type" : "article-journal", "volume" : "568" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[30]", "plainTextFormattedCitation" : "[30]", "previouslyFormattedCitation" : "[30]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[30]. Taken together what these data show is that RE is a potent stimulus for inducing changes in MPS, however, we know that in order to maximize the MPS response that protein consumption is necessary. When a sufficient, high quality dose of protein is consumed following RE there is a synergistic interaction between the post-meal hyperaminoacidemia and the contractile stimulus to further augment MPS ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "0002-9513 (Print)\\r0002-9513 (Linking)", "ISSN" : "0002-9513", "PMID" : "7900797", "abstract" : "The rates of protein synthesis and degradation and of amino acid transport were determined in the leg muscle of untrained postabsorptive normal volunteers at rest and approximately 3 h after a resistance exercise routine. The methodology involved use of stable isotopic tracers of amino acids, arteriovenous catheterization of the femoral vessels, and biopsy of the vastus lateralis muscle. During postexercise recovery, the rate of intramuscular phenylalanine utilization for protein synthesis increased above the basal value by 108 +/- 18%, whereas the rate of release from proteolysis increased by 51 +/- 17%. Muscle protein balance improved (P < 0.05) after exercise but did not become positive (from -15 +/- 12 to -6 +/- 3 nmol phenylalanine.min-1.100 ml leg volume-1). After exercise, rates of inward transport of leucine, lysine, and alanine increased (P < 0.05) above the basal state from 132 +/- 16 to 208 +/- 29, from 122 +/- 8 to 260 +/- 8, and from 384 +/- 71 to 602 +/- 89 nmol.min-1.100 ml leg-1, respectively. Transport of phenylalanine did not change significantly. These results indicate that, during recovery after resistance exercise, muscle protein turnover is increased because of an acceleration of synthesis and degradation. A postexercise acceleration of amino acid transport may contribute to the relatively greater stimulation of protein synthesis.", "author" : [ { "dropping-particle" : "", "family" : "Biolo", "given" : "G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Maggi", "given" : "S P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Williams", "given" : "B D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tipton", "given" : "K D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wolfe", "given" : "R R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The American journal of physiology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1995" ] ] }, "page" : "E514-E520", "title" : "Increased rates of muscle protein turnover and amino acid transport after resistance exercise in humans.", "type" : "article-journal", "volume" : "268" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1152/ajpregu.00077.2010", "ISBN" : "1522-1490 (Electronic) 0363-6119 (Linking)", "ISSN" : "0363-6119", "PMID" : "20519362", "abstract" : "Muscle protein breakdown (MPB) is increased following resistance exercise, but ingestion of carbohydrate during postexercise recovery can decrease MPB with no effect on muscle protein synthesis (MPS). We sought to determine whether a combination of essential amino acids (EAA) with low carbohydrate or high carbohydrate could effectively reduce MPB following resistance exercise and improve muscle protein net balance (NB). We hypothesized that higher levels of carbohydrate and resulting increases in circulating insulin would inhibit MPB and associated signaling, resulting in augmented NB. Thirteen male subjects were assigned to one of two groups receiving equivalent amounts of EAA (approximately 20 g) but differing carbohydrate levels (low = 30, high = 90 g). Groups ingested nutrients 1 h after an acute bout of leg resistance exercise. Leg phenylalanine kinetics (e.g., MPB, MPS, NB), signaling proteins, and mRNA expression were assessed on successive muscle biopsies using stable isotopic techniques, immunoblotting, and real-time quantitative PCR, respectively. MPB tended to decrease (P < 0.1) and MPS increased (P < 0.05) similarly in both groups following nutrient ingestion. No group differences were observed, but muscle ring finger 1 (MuRF1) protein content and MuRF1 mRNA expression increased following resistance exercise and remained elevated following nutrient ingestion, while autophagy marker (light-chain 3B-II) decreased after nutrient ingestion (P < 0.05). Forkhead box-O3a phosphorylation, total muscle atrophy F-box (MAFbx) protein, and MAFbx and caspase-3 mRNA expression were unchanged. We conclude that the enhanced muscle protein anabolic response detected when EAA+carbohydrate are ingested postresistance exercise is primarily due to an increase in MPS with minor changes in MPB, regardless of carbohydrate dose or circulating insulin level.", "author" : [ { "dropping-particle" : "", "family" : "Glynn", "given" : "Erin L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fry", "given" : "Christopher S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Drummond", "given" : "Micah J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Dreyer", "given" : "Hans C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Dhanani", "given" : "Shaheen", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Volpi", "given" : "Elena", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rasmussen", "given" : "Blake B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American journal of physiology. Regulatory, integrative and comparative physiology", "id" : "ITEM-2", "issued" : { "date-parts" : [ [ "2010" ] ] }, "page" : "R533-R540", "title" : "Muscle protein breakdown has a minor role in the protein anabolic response to essential amino acid and carbohydrate intake following resistance exercise.", "type" : "article-journal", "volume" : "299" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[28,31]", "plainTextFormattedCitation" : "[28,31]", "previouslyFormattedCitation" : "[28,31]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[28,31]. Thus, RE serves to ‘sensitize’ skeletal muscle to the anabolic impact of protein feeding. As such, repeated bouts of RE and protein ingestion often lead to expansion of the muscle protein pool and thus skeletal muscle hypertrophy. Although it is known that protein ingestion enhances RE-induced rates of MPS, the timing of protein ingestion has been shown to have an important mediating effect on MPS. Immediate post exercise consumption of high quality protein serves as an effective strategy to enhance MPS greater than RE alone ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "0002-9513 (Print) 0002-9513 (Linking)", "ISSN" : "0002-9513", "PMID" : "9252488", "abstract" : "Six normal untrained men were studied during the intravenous infusion of a balanced amino acid mixture (approximately 0.15 g.kg-1.h-1 for 3 h) at rest and after a leg resistance exercise routine to test the influence of exercise on the regulation of muscle protein kinetics by hyperaminoacidemia. Leg muscle protein kinetics and transport of selected amino acids (alanine, phenylalanine, leucine, and lysine) were isotopically determined using a model based on arteriovenous blood samples and muscle biopsy. The intravenous amino acid infusion resulted in comparable increases in arterial amino acid concentrations at rest and after exercise, whereas leg blood flow was 64 +/- 5% greater after exercise than at rest. During hyperaminoacidemia, the increases in amino acid transport above basal were 30-100% greater after exercise than at rest. Increases in muscle protein synthesis were also greater after exercise than at rest (291 +/- 42% vs. 141 +/- 45%). Muscle protein breakdown was not significantly affected by hyperminoacidemia either at rest or after exercise. We conclude that the stimulatory effect of exogenous amino acids on muscle protein synthesis is enhanced by prior exercise, perhaps in part because of enhanced blood flow. Our results imply that protein intake immediately after exercise may be more anabolic than when ingested at some later time.", "author" : [ { "dropping-particle" : "", "family" : "Biolo", "given" : "G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tipton", "given" : "K D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Klein", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wolfe", "given" : "R R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Physiol", "edition" : "1997/07/01", "id" : "ITEM-1", "issue" : "1 Pt 1", "issued" : { "date-parts" : [ [ "1997", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "E122-9", "title" : "An abundant supply of amino acids enhances the metabolic effect of exercise on muscle protein", "type" : "article-journal", "volume" : "273" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.3945/ajcn.2008.26401.INTRODUCTION", "ISBN" : "1938-3207 (Electronic) 0002-9165 (Linking)", "PMID" : "19056590", "abstract" : "BACKGROUND: The anabolic effect of resistance exercise is enhanced by the provision of dietary protein. OBJECTIVES: We aimed to determine the ingested protein dose response of muscle (MPS) and albumin protein synthesis (APS) after resistance exercise. In addition, we measured the phosphorylation of candidate signaling proteins thought to regulate acute changes in MPS. DESIGN: Six healthy young men reported to the laboratory on 5 separate occasions to perform an intense bout of leg-based resistance exercise. After exercise, participants consumed, in a randomized order, drinks containing 0, 5, 10, 20, or 40 g whole egg protein. Protein synthesis and whole-body leucine oxidation were measured over 4 h after exercise by a primed constant infusion of [1-(13)C]leucine. RESULTS: MPS displayed a dose response to dietary protein ingestion and was maximally stimulated at 20 g. The phosphorylation of ribosomal protein S6 kinase (Thr(389)), ribosomal protein S6 (Ser(240/244)), and the epsilon-subunit of eukaryotic initiation factor 2B (Ser(539)) were unaffected by protein ingestion. APS increased in a dose-dependent manner and also reached a plateau at 20 g ingested protein. Leucine oxidation was significantly increased after 20 and 40 g protein were ingested. CONCLUSIONS: Ingestion of 20 g intact protein is sufficient to maximally stimulate MPS and APS after resistance exercise. Phosphorylation of candidate signaling proteins was not enhanced with any dose of protein ingested, which suggested that the stimulation of MPS after resistance exercise may be related to amino acid availability. Finally, dietary protein consumed after exercise in excess of the rate at which it can be incorporated into tissue protein stimulates irreversible oxidation.", "author" : [ { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Robinson", "given" : "Meghann J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fry", "given" : "Jessica L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tang", "given" : "Jason E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Glover", "given" : "Elisa I", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilkinson", "given" : "Sarah B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Prior", "given" : "Todd", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tarnopolsky", "given" : "Mark A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Clin Nutr", "edition" : "2008/12/06", "id" : "ITEM-2", "issue" : "1", "issued" : { "date-parts" : [ [ "2009" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "161-168", "title" : "Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men", "type" : "article-journal", "volume" : "89" }, "uris" : [ "" ] }, { "id" : "ITEM-3", "itemData" : { "ISBN" : "0002-9513 (Print)\r0002-9513 (Linking)", "PMID" : "10198297", "abstract" : "We examined the response of net muscle protein synthesis to ingestion of amino acids after a bout of resistance exercise. A primed, constant infusion of L-[ring-2H5]phenylalanine was used to measure net muscle protein balance in three male and three female volunteers on three occasions. Subjects consumed in random order 1 liter of 1) a mixed amino acid (40 g) solution (MAA), 2) an essential amino acid (40 g) solution (EAA), and 3) a placebo solution (PLA). Arterial amino acid concentrations increased approximately 150-640% above baseline during ingestion of MAA and EAA. Net muscle protein balance was significantly increased from negative during PLA ingestion (-50 +/- 23 nmol. min-1. 100 ml leg volume-1) to positive during MAA ingestion (17 +/- 13 nmol. min-1. 100 ml leg volume-1) and EAA (29 +/- 14 nmol. min-1. 100 ml leg volume-1; P < 0.05). Because net balance was similar for MAA and EAA, it does not appear necessary to include nonessential amino acids in a formulation designed to elicit an anabolic response from muscle after exercise. We concluded that ingestion of oral essential amino acids results in a change from net muscle protein degradation to net muscle protein synthesis after heavy resistance exercise in humans similar to that seen when the amino acids were infused.", "author" : [ { "dropping-particle" : "", "family" : "Tipton", "given" : "K D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ferrando", "given" : "A A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Doyle Jr.", "given" : "D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wolfe", "given" : "R R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Physiol", "edition" : "1999/04/13", "id" : "ITEM-3", "issue" : "4 Pt 1", "issued" : { "date-parts" : [ [ "1999" ] ] }, "language" : "eng", "page" : "E628-34", "title" : "Postexercise net protein synthesis in human muscle from orally administered amino acids", "type" : "article-journal", "volume" : "276" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[32\u201334]", "plainTextFormattedCitation" : "[32\u201334]", "previouslyFormattedCitation" : "[32\u201334]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[32–34]. Timing of protein consumption is of critical importance as exercise induced stimulation of MPS is the greatest following exercise ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.91481.2008.", "author" : [ { "dropping-particle" : "", "family" : "Kumar", "given" : "Vinod", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Atherton", "given" : "Philip", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Smith", "given" : "Kenneth", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rennie", "given" : "Michael J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2009" ] ] }, "page" : "2026-2039", "title" : "Regulation of Protein Metabolism in Exercise and Recovery Human muscle protein synthesis and breakdown during and after exercise", "type" : "article-journal", "volume" : "106" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[35]", "plainTextFormattedCitation" : "[35]", "previouslyFormattedCitation" : "[35]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[35]. This concept has been termed the “anabolic window wherein a dose of protein, and subsequent hyperaminoacidemia, will have the greatest stimulatory effect when consumed in close temporal proximity following the performance of exercise. The duration of this anabolic window is, however, still debated. Dreyer and colleagues demonstrated that following an intense bout of RE in young males, that rates of MPS of the quadriceps were increased by 145% from baseline an hour following the immediate consumption of an essential-amino acid and carbohydrate beverage compared to a 41% increase following the consumption of a control beverage ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/ajpendo.00582.2007.", "abstract" : "We recently showed that resistance exercise and ingestion of essential amino acids with carbohydrate (EAA+CHO) can independently stimulate mammalian target of rapamycin (mTOR) signaling and muscle protein synthesis in humans. Providing an EAA+CHO solution postexercise can further increase muscle protein synthesis. Therefore, we hypothesized that enhanced mTOR signaling might be responsible for the greater muscle protein synthesis when leucine-enriched EAA+CHOs are ingested during postexercise recovery. Sixteen male subjects were randomized to one of two groups (control or EAA+CHO). The EAA+CHO group ingested the nutrient solution 1 h after resistance exercise. mTOR signaling was assessed by immunoblotting from repeated muscle biopsy samples. Mixed muscle fractional synthetic rate (FSR) was measured using stable isotope techniques. Muscle protein synthesis and 4E-BP1 phosphorylation during exercise were significantly reduced (P < 0.05). Postexercise FSR was elevated above baseline in both groups at 1 h but was even further elevated in the EAA+CHO group at 2 h postexercise (P < 0.05). Increased FSR was associated with enhanced phosphorylation of mTOR and S6K1 (P < 0.05). Akt phosphorylation was elevated at 1 h and returned to baseline by 2 h in the control group, but it remained elevated in the EAA+CHO group (P < 0.05). 4E-BP1 phosphorylation returned to baseline during recovery in control but became elevated when EAA+CHO was ingested (P < 0.05). eEF2 phosphorylation decreased at 1 and 2 h postexercise to a similar extent in both groups (P < 0.05). Our data suggest that enhanced activation of the mTOR signaling pathway is playing a role in the greater synthesis of muscle proteins when resistance exercise is followed by EAA+CHO ingestion.", "author" : [ { "dropping-particle" : "", "family" : "Dreyer", "given" : "Hans C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Drummond", "given" : "Micah J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pennings", "given" : "Bart", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fujita", "given" : "Satoshi", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Glynn", "given" : "Erin L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Chinkes", "given" : "David L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Dhanani", "given" : "Shaheen", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Volpi", "given" : "Elena", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rasmussen", "given" : "Blake B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hc", "given" : "Dreyer", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Mj", "given" : "Drummond", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pennings", "given" : "B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fujita", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "El", "given" : "Glynn", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Dl", "given" : "Chinkes", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Dhanani", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Volpi", "given" : "E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Leucine-enriched", "given" : "Rasmussen B B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Physiol Endocrinol Metab", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "392-400", "title" : "Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle", "type" : "article-journal", "volume" : "294" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[36]", "plainTextFormattedCitation" : "[36]", "previouslyFormattedCitation" : "[36]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[36]. West and et al, examined the MPS response 3-5 hours following a bout of RE in combination with the consumption of amino acids where they saw significant continued elevations in FSR ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/ajcn.111.013722", "ISBN" : "1938-3207 (Electronic)\\n0002-9165 (Linking)", "ISSN" : "00029165", "PMID" : "21795443", "abstract" : "Ingestion of whey or casein yields divergent patterns of aminoacidemia that influence whole-body and skeletal muscle myofibrillar protein synthesis (MPS) after exercise. Direct comparisons of the effects of contrasting absorption rates exhibited by these proteins are confounded by their differing amino acid contents.", "author" : [ { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Coffey", "given" : "Vernon G.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burke", "given" : "Louise M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hawley", "given" : "John a.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Stellingwerff", "given" : "Trent", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American Journal of Clinical Nutrition", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2011" ] ] }, "page" : "795-803", "title" : "Rapid aminoacidemia enhances myofibrillar protein synthesis and anabolic intramuscular signaling responses after resistance exercise", "type" : "article-journal", "volume" : "94" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[37]", "plainTextFormattedCitation" : "[37]", "previouslyFormattedCitation" : "[37]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[37]. Burd and colleagues then carried out similar investigation over a 24-hour period following RE to determine if this window would remain sensitive to protein feeding a full day after intense exercise. Groups performed one of three exercise sets; a high load (90% of the subjects maximal strength – 1RM) until volitional failure, a work matched set with a low load (30% 1RM, matched) or at a low load until volitional failure (30% 1RM, failure). Interestingly, it was only when exercise was performed to failure, that sensitization of the quadriceps muscle remained elevated 24-hours following the protocol alluding to the concept that perhaps it is a high recruitment of the muscle, particularly type II fibers, that are required for maximum sensitization to aminoacidemia ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/jn.110.135038\rjn.110.135038 [pii]", "ISBN" : "1541-6100 (Electronic)\r0022-3166 (Linking)", "PMID" : "21289204", "abstract" : "We aimed to determine whether an exercise-mediated enhancement of muscle protein synthesis to feeding persisted 24 h after resistance exercise. We also determined the impact of different exercise intensities (90% or 30% maximal strength) or contraction volume (work-matched or to failure) on the response at 24 h of recovery. Fifteen men (21 +/- 1 y, BMI = 24.1 +/- 0.8 kg . m(-2)) received a primed, constant infusion of l-[ring-(13)C(6)]phenylalanine to measure muscle protein synthesis after protein feeding at rest (FED; 15 g whey protein) and 24 h after resistance exercise (EX-FED). Participants performed unilateral leg exercises: 1) 4 sets at 90% of maximal strength to failure (90FAIL); 2) 30% work-matched to 90FAIL (30WM); or 3) 30% to failure (30FAIL). Regardless of condition, rates of mixed muscle protein and sarcoplasmic protein synthesis were similarly stimulated at FED and EX-FED. In contrast, protein ingestion stimulated rates of myofibrillar protein synthesis above fasting rates by 0.016 +/- 0.002%/h and the response was enhanced 24 h after resistance exercise, but only in the 90FAIL and 30FAIL conditions, by 0.038 +/- 0.012 and 0.041 +/- 0.010, respectively. Phosphorylation of protein kinase B on Ser473 was greater than FED at EX-FED only in 90FAIL, whereas phosphorylation of mammalian target of rapamycin on Ser2448 was significantly increased at EX-FED above FED only in the 30FAIL condition. Our results suggest that resistance exercise performed until failure confers a sensitizing effect on human skeletal muscle for at least 24 h that is specific to the myofibrillar protein fraction.", "author" : [ { "dropping-particle" : "", "family" : "Burd", "given" : "N A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "D W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moore", "given" : "D R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Atherton", "given" : "P J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staples", "given" : "A W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Prior", "given" : "T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tang", "given" : "J E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rennie", "given" : "M J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "S K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Nutr", "edition" : "2011/02/04", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2011" ] ] }, "language" : "eng", "page" : "568-573", "title" : "Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men", "type" : "article-journal", "volume" : "141" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[38]", "plainTextFormattedCitation" : "[38]", "previouslyFormattedCitation" : "[38]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[38]. Taken together, what these data highlight is that RE serves to sensitize skeletal muscle to the anabolic impact of amino acid ingestion; however, this an effect that can persist for up to 48 h following the cessation of a maximal exercise bout (Figure i).0-457200228600-149860Figure i. Resistance exercise stimulates a prolonged elevation in MPS that can remain elevatd for up to 48 hours; used, with permission, from Churchward-Venne et al., 2012 ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "1743-7075-9-40 [pii] 10.1186/1743-7075-9-40", "ISBN" : "1743-7075 (Electronic) 1743-7075 (Linking)", "PMID" : "22594765", "abstract" : "Provision of dietary amino acids increases skeletal muscle protein synthesis (MPS), an effect that is enhanced by prior resistance exercise. As a fundamentally necessary process in the enhancement of muscle mass, strategies to enhance rates of MPS would be beneficial in the development of interventions aimed at increasing skeletal muscle mass particularly when combined with chronic resistance exercise. The purpose of this review article is to provide an update on current findings regarding the nutritional regulation of MPS and highlight nutrition based strategies that may serve to maximize skeletal muscle protein anabolism with resistance exercise. Such factors include timing of protein intake, dietary protein type, the role of leucine as a key anabolic amino acid, and the impact of other macronutrients (i.e. carbohydrate) on the regulation of MPS after resistance exercise. We contend that nutritional strategies that serve to maximally stimulate MPS may be useful in the development of nutrition and exercise based interventions aimed at enhancing skeletal muscle mass which may be of interest to elderly populations and to athletes.", "author" : [ { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "T A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "N A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Research Group", "given" : "E M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Nutr Metab (Lond)", "edition" : "2012/05/19", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "40", "title" : "Nutritional regulation of muscle protein synthesis with resistance exercise: strategies to enhance anabolism", "type" : "article-journal", "volume" : "9" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[27]", "plainTextFormattedCitation" : "[27]", "previouslyFormattedCitation" : "[27]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[27].Figure i. Resistance exercise stimulates a prolonged elevation in MPS that can remain elevatd for up to 48 hours; used, with permission, from Churchward-Venne et al., 2012 ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "1743-7075-9-40 [pii] 10.1186/1743-7075-9-40", "ISBN" : "1743-7075 (Electronic) 1743-7075 (Linking)", "PMID" : "22594765", "abstract" : "Provision of dietary amino acids increases skeletal muscle protein synthesis (MPS), an effect that is enhanced by prior resistance exercise. As a fundamentally necessary process in the enhancement of muscle mass, strategies to enhance rates of MPS would be beneficial in the development of interventions aimed at increasing skeletal muscle mass particularly when combined with chronic resistance exercise. The purpose of this review article is to provide an update on current findings regarding the nutritional regulation of MPS and highlight nutrition based strategies that may serve to maximize skeletal muscle protein anabolism with resistance exercise. Such factors include timing of protein intake, dietary protein type, the role of leucine as a key anabolic amino acid, and the impact of other macronutrients (i.e. carbohydrate) on the regulation of MPS after resistance exercise. We contend that nutritional strategies that serve to maximally stimulate MPS may be useful in the development of nutrition and exercise based interventions aimed at enhancing skeletal muscle mass which may be of interest to elderly populations and to athletes.", "author" : [ { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "T A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "N A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Research Group", "given" : "E M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Nutr Metab (Lond)", "edition" : "2012/05/19", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "40", "title" : "Nutritional regulation of muscle protein synthesis with resistance exercise: strategies to enhance anabolism", "type" : "article-journal", "volume" : "9" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[27]", "plainTextFormattedCitation" : "[27]", "previouslyFormattedCitation" : "[27]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[27].Evidently, protein ingestion has the ability to maximize the acute MPS response following RE though it is ultimately the sum of frequent episodic bouts of heightened anabolism resulting from chronic RT that are fundamental for the augmentation of lean mass. Willoughby and colleagues ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00726-006-0398-7", "ISBN" : "0939-4451", "ISSN" : "09394451", "PMID" : "16988909", "abstract" : "This study examined 10 wks of resistance training and the ingestion of supplemental protein and amino acids on muscle performance and markers of muscle anabolism. Nineteen untrained males were randomly assigned to supplement groups containing either 20 g protein (14 g whey and casein protein, 6 g free amino acids) or 20 g dextrose placebo ingested 1 h before and after exercise for a total of 40 g/d. Participants exercised 4 times/wk using 3 sets of 6-8 repetitions at 85-90% of the one repetition maximum. Data were analyzed with two-way ANOVA (p < 0.05). The protein supplement resulted in greater increases in total body mass, fat-free mass, thigh mass, muscle strength, serum IGF-1, IGF-1 mRNA, MHC I and IIa expression, and myofibrillar protein. Ten-wks of resistance training with 20 g protein and amino acids ingested 1 h before and after exercise is more effective than carbohydrate placebo in up-regulating markers of muscle protein synthesis and anabolism along with subsequent improvements in muscle performance.", "author" : [ { "dropping-particle" : "", "family" : "Willoughby", "given" : "D. S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Stout", "given" : "J. R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilborn", "given" : "C. D.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Amino Acids", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2007" ] ] }, "page" : "467-477", "title" : "Effects of resistance training and protein plus amino acid supplementation on muscle anabolism, mass, and strength", "type" : "article-journal", "volume" : "32" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[39]", "plainTextFormattedCitation" : "[39]", "previouslyFormattedCitation" : "[39]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[39] examined whether supplementation with protein before and after RE would result in greater gains in fat free mass than a placebo control over a 10-week training period. Nineteen untrained young men participated in RT 4 times peer week and consumed either a total of 40 grams of protein before and after training or a placebo control composed of dextrose. Following the training period, individuals consuming the protein supplement had a greater increase in body mass (2.65 kg), fat free mass (2.93 kg), and thigh mass (0.32 kg) compared to the placebo control ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00726-006-0398-7", "ISBN" : "0939-4451", "ISSN" : "09394451", "PMID" : "16988909", "abstract" : "This study examined 10 wks of resistance training and the ingestion of supplemental protein and amino acids on muscle performance and markers of muscle anabolism. Nineteen untrained males were randomly assigned to supplement groups containing either 20 g protein (14 g whey and casein protein, 6 g free amino acids) or 20 g dextrose placebo ingested 1 h before and after exercise for a total of 40 g/d. Participants exercised 4 times/wk using 3 sets of 6-8 repetitions at 85-90% of the one repetition maximum. Data were analyzed with two-way ANOVA (p < 0.05). The protein supplement resulted in greater increases in total body mass, fat-free mass, thigh mass, muscle strength, serum IGF-1, IGF-1 mRNA, MHC I and IIa expression, and myofibrillar protein. Ten-wks of resistance training with 20 g protein and amino acids ingested 1 h before and after exercise is more effective than carbohydrate placebo in up-regulating markers of muscle protein synthesis and anabolism along with subsequent improvements in muscle performance.", "author" : [ { "dropping-particle" : "", "family" : "Willoughby", "given" : "D. S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Stout", "given" : "J. R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilborn", "given" : "C. D.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Amino Acids", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2007" ] ] }, "page" : "467-477", "title" : "Effects of resistance training and protein plus amino acid supplementation on muscle anabolism, mass, and strength", "type" : "article-journal", "volume" : "32" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[39]", "plainTextFormattedCitation" : "[39]", "previouslyFormattedCitation" : "[39]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[39]. Similarly, Kerksick et al. ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Kerksick", "given" : "Chad M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rasmussen", "given" : "Christopher J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lancaster", "given" : "Stacy L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Magu", "given" : "Bharat", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Smith", "given" : "Penney", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Melton", "given" : "Charles", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Greenwood", "given" : "Michael", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Almada", "given" : "Anthony L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Earnest", "given" : "Conrad P.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kreider", "given" : "Richard B.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Strength and Conditioning Research", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2006" ] ] }, "page" : "643-653", "title" : "The Effects of Protein and Amino Acid Supplementation on Performance and Training Adaptations During Ten Weeks of Resistance Training", "type" : "article-journal", "volume" : "20" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[40]", "plainTextFormattedCitation" : "[40]", "previouslyFormattedCitation" : "[40]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[40] examined the effects of protein consumption and exercise on body composition over 10 weeks. Participants were randomized to consume either 42 grams of protein or a placebo control immediately following exercise. Ingestion of protein resulted in an increase in lean mass of 1.9 kg while ingestion of the placebo beverage resulted in no change in total lean body mass ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Kerksick", "given" : "Chad M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rasmussen", "given" : "Christopher J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lancaster", "given" : "Stacy L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Magu", "given" : "Bharat", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Smith", "given" : "Penney", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Melton", "given" : "Charles", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Greenwood", "given" : "Michael", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Almada", "given" : "Anthony L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Earnest", "given" : "Conrad P.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kreider", "given" : "Richard B.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Strength and Conditioning Research", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2006" ] ] }, "page" : "643-653", "title" : "The Effects of Protein and Amino Acid Supplementation on Performance and Training Adaptations During Ten Weeks of Resistance Training", "type" : "article-journal", "volume" : "20" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[40]", "plainTextFormattedCitation" : "[40]", "previouslyFormattedCitation" : "[40]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[40]. It is also important to consider the timing of protein ingestion and its effects over a training period. Cribb and colleagues ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "(3).pdf", "abstract" : "PURPOSE: Some studies report greater muscle hypertrophy during resistance exercise (RE) training from supplement timing (i.e., the strategic consumption of protein and carbohydrate before and/or after each workout). However, no studies have examined whether this strategy provides greater muscle hypertrophy or strength development compared with supplementation at other times during the day. The purpose of this study was to examine the effects of supplement timing compared with supplementation in the hours not close to the workout on muscle-fiber hypertrophy, strength, and body composition during a 10-wk RE program. METHODS: In a single-blind, randomized protocol, resistance-trained males were matched for strength and placed into one of two groups; the PRE-POST group consumed a supplement (1 g x kg(-1) body weight) containing protein/creatine/glucose immediately before and after RE. The MOR-EVE group consumed the same dose of the same supplement in the morning and late evening. All assessments were completed the week before and after 10 wk of structured, supervised RE training. Assessments included strength (1RM, three exercises), body composition (DEXA), and vastus lateralis muscle biopsies for determination of muscle fiber type (I, IIa, IIx), cross-sectional area (CSA), contractile protein, creatine (Cr), and glycogen content. RESULTS: PRE-POST demonstrated a greater (P < 0.05) increase in lean body mass and 1RM strength in two of three assessments. The changes in body composition were supported by a greater (P < 0.05) increase in CSA of the type II fibers and contractile protein content. PRE-POST supplementation also resulted in higher muscle Cr and glycogen values after the training program (P < 0.05). CONCLUSION: Supplement timing represents a simple but effective strategy that enhances the adaptations desired from RE-training.", "author" : [ { "dropping-particle" : "", "family" : "Cribb", "given" : "Pj", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hayes", "given" : "Alan", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Med Sci Sports Exerc", "id" : "ITEM-1", "issue" : "11", "issued" : { "date-parts" : [ [ "2006" ] ] }, "page" : "1918-25", "title" : "Effects of Supplement-Timing and Resistance Exercise on Skeletal Muscle Hypertrophy", "type" : "article-journal", "volume" : "38" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[41]", "plainTextFormattedCitation" : "[41]", "previouslyFormattedCitation" : "[41]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[41] examined the effects of protein supplementation timing in recreational male body builders. Participants were randomized to consume 40 grams of protein either PRE-POST (prior to and immediately following RE) or MOR-EVE (prior to breakfast and prior to sleep) on each training day, 4 times per week for 10 weeks. Individuals consuming protein in the PRE-POST pattern were able to significantly increase lean body mass by 2.8 kg compared to 1.5 kg in those consuming protein in the MOR-EVE pattern. Similarly, the PRE-POST supplementation group demonstrated an increase in the CSA of type IIa and type IIx fibers by 25% and 25.3% respectively following the 10-week protocol compared to a 17% and 17.8% increase in the MOR-EVE group. Taken together, protein consumption in close temporal proximity to a RE bout results in significant lean mass increases when performed chronically. Therefore several factors should be taken into account when aiming to maximize RE-induced lean mass gains with protein consumption.III.ii Role of Protein Dose and QualityProtein quality and dose are also critical when targeting maximal increases in lean mass accrual. Protein quality was previously defined with the use of the protein digestibility-corrected amino acid score (PDCAAS), which defines proteins according to their essential amino acid content and digestibility relative to the reference (egg) protein ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "9789251074176", "ISSN" : "0254-4725", "author" : [ { "dropping-particle" : "", "family" : "FAO", "given" : "", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "FAO food and nutrition paper", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2011" ] ] }, "number-of-pages" : "1-79", "title" : "Dietary protein quality evaluation in human nutrition", "type" : "report" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[42]", "plainTextFormattedCitation" : "[42]", "previouslyFormattedCitation" : "[42]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[42]. This amino acid score is used to predict protein quality to determine the potential capacity of the protein in food sources to provide amino acid needs. The importance of amino acid digestibility is crucial as undigested dietary proteins may be unabsorbed and excreted rather than being absorbed in the small intestine or contributions to lean mass ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1017/S0007114512002528", "ISSN" : "0007-1145", "PMID" : "23107541", "abstract" : "Available amino acids are those absorbed from the gastrointestinal tract in a form suitable for body protein synthesis. True ileal digestible amino acids are determined based on the difference between dietary amino acid intake and unabsorbed dietary amino acids at the terminal ileum. The accuracy of ileal digestible amino acid estimates for predicting available amino acid content depends on several factors, including the accuracy of the amino acid analysis procedure. In heat processed foods, lysine can react with compounds to form nutritionally unavailable derivatives that are unstable during the hydrochloric acid hydrolysis step of amino acid analysis and can revert back to lysine causing an overestimate of available lysine. Recently, the true ileal digestible reactive (available) lysine assay based on guanidination has provided a means of accurately determining available lysine in processed foods. Methionine can be oxidised during processing to form methionine sulphoxide and methionine sulphone and cysteine oxidised to cysteic acid. Methionine sulphoxide, but not methionine sulphone or cysteic acid, is partially nutritionally available in some species of animal. Currently, methionine and cysteine are determined as methionine sulphone and cysteic acid respectively after quantitative oxidation prior to acid hydrolysis. Consequently, methionine and cysteine are overestimated if methionine sulphone or cysteic acid are present in the original material. Overall, given the problems associated with the analysis of some amino acids in processed foodstuffs, the available amino acid content may not always be accurately predicted by true ileal amino acid digestibility estimates. For such amino acids specific analytical strategies may be required.", "author" : [ { "dropping-particle" : "", "family" : "Rutherfurd", "given" : "Shane M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moughan", "given" : "Paul J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "British Journal of Nutrition", "id" : "ITEM-1", "issue" : "S2", "issued" : { "date-parts" : [ [ "2012" ] ] }, "page" : "S298-S305", "title" : "Available versus digestible dietary amino acids", "type" : "article-journal", "volume" : "108" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[43]", "plainTextFormattedCitation" : "[43]", "previouslyFormattedCitation" : "[43]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[43]. Proteins with the highest digestibility and quality scores are given a maximum value of 1.0 and include casein protein, soy protein, whey protein and egg protein ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISSN" : "13032968", "PMID" : "24482589", "abstract" : "Protein intake that exceeds the recommended daily allowance is widely accepted for both endurance and power athletes. However, considering the variety of proteins that are available much less is known concerning the benefits of consuming one protein versus another. The purpose of this paper is to identify and analyze key factors in order to make responsible recommendations to both the general and athletic populations. Evaluation of a protein is fundamental in determining its appropriateness in the human diet. Proteins that are of inferior content and digestibility are important to recognize and restrict or limit in the diet. Similarly, such knowledge will provide an ability to identify proteins that provide the greatest benefit and should be consumed. The various techniques utilized to rate protein will be discussed. Traditionally, sources of dietary protein are seen as either being of animal or vegetable origin. Animal sources provide a complete source of protein (i.e. containing all essential amino acids), whereas vegetable sources generally lack one or more of the essential amino acids. Animal sources of dietary protein, despite providing a complete protein and numerous vitamins and minerals, have some health professionals concerned about the amount of saturated fat common in these foods compared to vegetable sources. The advent of processing techniques has shifted some of this attention and ignited the sports supplement marketplace with derivative products such as whey, casein and soy. Individually, these products vary in quality and applicability to certain populations. The benefits that these particular proteins possess are discussed. In addition, the impact that elevated protein consumption has on health and safety issues (i.e. bone health, renal function) are also reviewed. Key PointsHigher protein needs are seen in athletic populations.Animal proteins is an important source of protein, however potential health concerns do exist from a diet of protein consumed from primarily animal sources.With a proper combination of sources, vegetable proteins may provide similar benefits as protein from animal sources.Casein protein supplementation may provide the greatest benefit for increases in protein synthesis for a prolonged duration.", "author" : [ { "dropping-particle" : "", "family" : "Hoffman", "given" : "Jay R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Falvo", "given" : "Michael J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Sports Science and Medicine", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2004" ] ] }, "page" : "118-130", "title" : "Protein - Which is best?", "type" : "article-journal", "volume" : "3" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[44]", "plainTextFormattedCitation" : "[44]", "previouslyFormattedCitation" : "[44]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[44]. More recently, the Food and Agriculture Organization (FAO) has endorsed the digestible indispensible amino acid score (DIAAS) to assess protein quality which improves upon the PDCAAS as it is able to distinguish between proteins that were previously classed at an equivalent value ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/jn.114.195438.1", "author" : [ { "dropping-particle" : "", "family" : "Rutherfurd", "given" : "Shane M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fanning", "given" : "Aaron C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Miller", "given" : "Bruce J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moughan", "given" : "Paul J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Nutrition", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2015" ] ] }, "page" : "1-8", "title" : "Protein Digestibility-Corrected Amino Acid Scores and Digestible Indispensable Amino Acid Scores Differentially Describe Protein Quality in Growing Male Rats", "type" : "article-journal", "volume" : "jn-144" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[45]", "plainTextFormattedCitation" : "[45]", "previouslyFormattedCitation" : "[45]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[45]. The DIAAS score also samples protein digestibility from the ileum rather than from fecal matter as was measured for the determination of the PDCAAS. Using the DIAAS, proteins with the highest digestibility and quality scores are the two main milk proteins casein and whey, which have scores of 1.18 and 1.09, respectively. These DIAAS scores for casein and whey are in comparison to soy protein which was given a value of 0.91 but was previously scored as equivalent to milk proteins under the PDCAAS at 1.0 ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/jn.114.195438.1", "author" : [ { "dropping-particle" : "", "family" : "Rutherfurd", "given" : "Shane M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fanning", "given" : "Aaron C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Miller", "given" : "Bruce J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moughan", "given" : "Paul J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Nutrition", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2015" ] ] }, "page" : "1-8", "title" : "Protein Digestibility-Corrected Amino Acid Scores and Digestible Indispensable Amino Acid Scores Differentially Describe Protein Quality in Growing Male Rats", "type" : "article-journal", "volume" : "jn-144" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[45]", "plainTextFormattedCitation" : "[45]", "previouslyFormattedCitation" : "[45]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[45]. The impact of the difference in proteins, reflective of the DIAAS scores, was shown by Wilkinson et al. ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "85/4/1031 [pii]", "ISBN" : "0002-9165 (Print)\r0002-9165 (Linking)", "PMID" : "17413102", "abstract" : "BACKGROUND: Resistance exercise leads to net muscle protein accretion through a synergistic interaction of exercise and feeding. Proteins from different sources may differ in their ability to support muscle protein accretion because of different patterns of postprandial hyperaminoacidemia. OBJECTIVE: We examined the effect of consuming isonitrogenous, isoenergetic, and macronutrient-matched soy or milk beverages (18 g protein, 750 kJ) on protein kinetics and net muscle protein balance after resistance exercise in healthy young men. Our hypothesis was that soy ingestion would result in larger but transient hyperaminoacidemia compared with milk and that milk would promote a greater net balance because of lower but prolonged hyperaminoacidemia. DESIGN: Arterial-venous amino acid balance and muscle fractional synthesis rates were measured in young men who consumed fluid milk or a soy-protein beverage in a crossover design after a bout of resistance exercise. RESULTS: Ingestion of both soy and milk resulted in a positive net protein balance. Analysis of area under the net balance curves indicated an overall greater net balance after milk ingestion (P < 0.05). The fractional synthesis rate in muscle was also greater after milk consumption (0.10 +/- 0.01%/h) than after soy consumption (0.07 +/- 0.01%/h; P = 0.05). CONCLUSIONS: Milk-based proteins promote muscle protein accretion to a greater extent than do soy-based proteins when consumed after resistance exercise. The consumption of either milk or soy protein with resistance training promotes muscle mass maintenance and gains, but chronic consumption of milk proteins after resistance exercise likely supports a more rapid lean mass accrual.", "author" : [ { "dropping-particle" : "", "family" : "Wilkinson", "given" : "S B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tarnopolsky", "given" : "M A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Macdonald", "given" : "M J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Macdonald", "given" : "J R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Armstrong", "given" : "D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Clin Nutr", "edition" : "2007/04/07", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2007" ] ] }, "language" : "eng", "page" : "1031-1040", "title" : "Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise than does consumption of an isonitrogenous and isoenergetic soy-protein beverage", "type" : "article-journal", "volume" : "85" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[46]", "plainTextFormattedCitation" : "[46]", "previouslyFormattedCitation" : "[46]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[46] who investigated the acute effects of either fluid skimmed milk (containing both whey and casein protein in a ratio of 1:4) or an isonitrogenous soy protein beverage on MPS three hours following acute maximal RE. Milk ingestion (500mL) resulted in an FSR of 0.1%/h which was significantly greater than that stimulated by soy protein of 0.07%/h ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "85/4/1031 [pii]", "ISBN" : "0002-9165 (Print)\r0002-9165 (Linking)", "PMID" : "17413102", "abstract" : "BACKGROUND: Resistance exercise leads to net muscle protein accretion through a synergistic interaction of exercise and feeding. Proteins from different sources may differ in their ability to support muscle protein accretion because of different patterns of postprandial hyperaminoacidemia. OBJECTIVE: We examined the effect of consuming isonitrogenous, isoenergetic, and macronutrient-matched soy or milk beverages (18 g protein, 750 kJ) on protein kinetics and net muscle protein balance after resistance exercise in healthy young men. Our hypothesis was that soy ingestion would result in larger but transient hyperaminoacidemia compared with milk and that milk would promote a greater net balance because of lower but prolonged hyperaminoacidemia. DESIGN: Arterial-venous amino acid balance and muscle fractional synthesis rates were measured in young men who consumed fluid milk or a soy-protein beverage in a crossover design after a bout of resistance exercise. RESULTS: Ingestion of both soy and milk resulted in a positive net protein balance. Analysis of area under the net balance curves indicated an overall greater net balance after milk ingestion (P < 0.05). The fractional synthesis rate in muscle was also greater after milk consumption (0.10 +/- 0.01%/h) than after soy consumption (0.07 +/- 0.01%/h; P = 0.05). CONCLUSIONS: Milk-based proteins promote muscle protein accretion to a greater extent than do soy-based proteins when consumed after resistance exercise. The consumption of either milk or soy protein with resistance training promotes muscle mass maintenance and gains, but chronic consumption of milk proteins after resistance exercise likely supports a more rapid lean mass accrual.", "author" : [ { "dropping-particle" : "", "family" : "Wilkinson", "given" : "S B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tarnopolsky", "given" : "M A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Macdonald", "given" : "M J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Macdonald", "given" : "J R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Armstrong", "given" : "D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Clin Nutr", "edition" : "2007/04/07", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2007" ] ] }, "language" : "eng", "page" : "1031-1040", "title" : "Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise than does consumption of an isonitrogenous and isoenergetic soy-protein beverage", "type" : "article-journal", "volume" : "85" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[46]", "plainTextFormattedCitation" : "[46]", "previouslyFormattedCitation" : "[46]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[46]. When translated into chronic consumption, during a 12-week resistance training protocol, Hartman and colleagues ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "86/2/373 [pii]", "ISBN" : "0002-9165 (Print)\r0002-9165 (Linking)", "PMID" : "17684208", "abstract" : "BACKGROUND: Acute consumption of fat-free fluid milk after resistance exercise promotes a greater positive protein balance than does soy protein. OBJECTIVE: We aimed to determine the long-term consequences of milk or soy protein or equivalent energy consumption on training-induced lean mass accretion. DESIGN: We recruited 56 healthy young men who trained 5 d/wk for 12 wk on a rotating split-body resistance exercise program in a parallel 3-group longitudinal design. Subjects were randomly assigned to consume drinks immediately and again 1 h after exercise: fat-free milk (Milk; n = 18); fat-free soy protein (Soy; n = 19) that was isoenergetic, isonitrogenous, and macronutrient ratio matched to Milk; or maltodextrin that was isoenergetic with Milk and Soy (control group; n = 19). RESULTS: Muscle fiber size, maximal strength, and body composition by dual-energy X-ray absorptiometry (DXA) were measured before and after training. No between-group differences were seen in strength. Type II muscle fiber area increased in all groups with training, but with greater increases in the Milk group than in both the Soy and control groups (P < 0.05). Type I muscle fiber area increased after training only in the Milk and Soy groups, with the increase in the Milk group being greater than that in the control group (P < 0.05). DXA-measured fat- and bone-free mass increased in all groups, with a greater increase in the Milk group than in both the Soy and control groups (P < 0.05). CONCLUSION: We conclude that chronic postexercise consumption of milk promotes greater hypertrophy during the early stages of resistance training in novice weightlifters when compared with isoenergetic soy or carbohydrate consumption.", "author" : [ { "dropping-particle" : "", "family" : "Hartman", "given" : "J W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tang", "given" : "J E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilkinson", "given" : "S B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tarnopolsky", "given" : "M A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lawrence", "given" : "R L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "V", "family" : "Fullerton", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Clin Nutr", "edition" : "2007/08/09", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2007" ] ] }, "language" : "eng", "page" : "373-381", "title" : "Consumption of fat-free fluid milk after resistance exercise promotes greater lean mass accretion than does consumption of soy or carbohydrate in young, novice, male weightlifters", "type" : "article-journal", "volume" : "86" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[47]", "plainTextFormattedCitation" : "[47]", "previouslyFormattedCitation" : "[47]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[47] demonstrated a significantly greater increase in lean body mass and Type II muscle fiber cross-sectional area only in participants consuming milk as a post-exercise supplement versus a soy beverage or an isoenergetic control ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "86/2/373 [pii]", "ISBN" : "0002-9165 (Print)\r0002-9165 (Linking)", "PMID" : "17684208", "abstract" : "BACKGROUND: Acute consumption of fat-free fluid milk after resistance exercise promotes a greater positive protein balance than does soy protein. OBJECTIVE: We aimed to determine the long-term consequences of milk or soy protein or equivalent energy consumption on training-induced lean mass accretion. DESIGN: We recruited 56 healthy young men who trained 5 d/wk for 12 wk on a rotating split-body resistance exercise program in a parallel 3-group longitudinal design. Subjects were randomly assigned to consume drinks immediately and again 1 h after exercise: fat-free milk (Milk; n = 18); fat-free soy protein (Soy; n = 19) that was isoenergetic, isonitrogenous, and macronutrient ratio matched to Milk; or maltodextrin that was isoenergetic with Milk and Soy (control group; n = 19). RESULTS: Muscle fiber size, maximal strength, and body composition by dual-energy X-ray absorptiometry (DXA) were measured before and after training. No between-group differences were seen in strength. Type II muscle fiber area increased in all groups with training, but with greater increases in the Milk group than in both the Soy and control groups (P < 0.05). Type I muscle fiber area increased after training only in the Milk and Soy groups, with the increase in the Milk group being greater than that in the control group (P < 0.05). DXA-measured fat- and bone-free mass increased in all groups, with a greater increase in the Milk group than in both the Soy and control groups (P < 0.05). CONCLUSION: We conclude that chronic postexercise consumption of milk promotes greater hypertrophy during the early stages of resistance training in novice weightlifters when compared with isoenergetic soy or carbohydrate consumption.", "author" : [ { "dropping-particle" : "", "family" : "Hartman", "given" : "J W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tang", "given" : "J E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilkinson", "given" : "S B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tarnopolsky", "given" : "M A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lawrence", "given" : "R L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "V", "family" : "Fullerton", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Clin Nutr", "edition" : "2007/08/09", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2007" ] ] }, "language" : "eng", "page" : "373-381", "title" : "Consumption of fat-free fluid milk after resistance exercise promotes greater lean mass accretion than does consumption of soy or carbohydrate in young, novice, male weightlifters", "type" : "article-journal", "volume" : "86" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[47]", "plainTextFormattedCitation" : "[47]", "previouslyFormattedCitation" : "[47]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[47]. The results of Wilkinson et al. ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "85/4/1031 [pii]", "ISBN" : "0002-9165 (Print)\r0002-9165 (Linking)", "PMID" : "17413102", "abstract" : "BACKGROUND: Resistance exercise leads to net muscle protein accretion through a synergistic interaction of exercise and feeding. Proteins from different sources may differ in their ability to support muscle protein accretion because of different patterns of postprandial hyperaminoacidemia. OBJECTIVE: We examined the effect of consuming isonitrogenous, isoenergetic, and macronutrient-matched soy or milk beverages (18 g protein, 750 kJ) on protein kinetics and net muscle protein balance after resistance exercise in healthy young men. Our hypothesis was that soy ingestion would result in larger but transient hyperaminoacidemia compared with milk and that milk would promote a greater net balance because of lower but prolonged hyperaminoacidemia. DESIGN: Arterial-venous amino acid balance and muscle fractional synthesis rates were measured in young men who consumed fluid milk or a soy-protein beverage in a crossover design after a bout of resistance exercise. RESULTS: Ingestion of both soy and milk resulted in a positive net protein balance. Analysis of area under the net balance curves indicated an overall greater net balance after milk ingestion (P < 0.05). The fractional synthesis rate in muscle was also greater after milk consumption (0.10 +/- 0.01%/h) than after soy consumption (0.07 +/- 0.01%/h; P = 0.05). CONCLUSIONS: Milk-based proteins promote muscle protein accretion to a greater extent than do soy-based proteins when consumed after resistance exercise. The consumption of either milk or soy protein with resistance training promotes muscle mass maintenance and gains, but chronic consumption of milk proteins after resistance exercise likely supports a more rapid lean mass accrual.", "author" : [ { "dropping-particle" : "", "family" : "Wilkinson", "given" : "S B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tarnopolsky", "given" : "M A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Macdonald", "given" : "M J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Macdonald", "given" : "J R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Armstrong", "given" : "D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Clin Nutr", "edition" : "2007/04/07", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2007" ] ] }, "language" : "eng", "page" : "1031-1040", "title" : "Consumption of fluid skim milk promotes greater muscle protein accretion after resistance exercise than does consumption of an isonitrogenous and isoenergetic soy-protein beverage", "type" : "article-journal", "volume" : "85" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[46]", "plainTextFormattedCitation" : "[46]", "previouslyFormattedCitation" : "[46]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[46] and Hartman et al. ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "86/2/373 [pii]", "ISBN" : "0002-9165 (Print)\r0002-9165 (Linking)", "PMID" : "17684208", "abstract" : "BACKGROUND: Acute consumption of fat-free fluid milk after resistance exercise promotes a greater positive protein balance than does soy protein. OBJECTIVE: We aimed to determine the long-term consequences of milk or soy protein or equivalent energy consumption on training-induced lean mass accretion. DESIGN: We recruited 56 healthy young men who trained 5 d/wk for 12 wk on a rotating split-body resistance exercise program in a parallel 3-group longitudinal design. Subjects were randomly assigned to consume drinks immediately and again 1 h after exercise: fat-free milk (Milk; n = 18); fat-free soy protein (Soy; n = 19) that was isoenergetic, isonitrogenous, and macronutrient ratio matched to Milk; or maltodextrin that was isoenergetic with Milk and Soy (control group; n = 19). RESULTS: Muscle fiber size, maximal strength, and body composition by dual-energy X-ray absorptiometry (DXA) were measured before and after training. No between-group differences were seen in strength. Type II muscle fiber area increased in all groups with training, but with greater increases in the Milk group than in both the Soy and control groups (P < 0.05). Type I muscle fiber area increased after training only in the Milk and Soy groups, with the increase in the Milk group being greater than that in the control group (P < 0.05). DXA-measured fat- and bone-free mass increased in all groups, with a greater increase in the Milk group than in both the Soy and control groups (P < 0.05). CONCLUSION: We conclude that chronic postexercise consumption of milk promotes greater hypertrophy during the early stages of resistance training in novice weightlifters when compared with isoenergetic soy or carbohydrate consumption.", "author" : [ { "dropping-particle" : "", "family" : "Hartman", "given" : "J W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tang", "given" : "J E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilkinson", "given" : "S B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tarnopolsky", "given" : "M A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lawrence", "given" : "R L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "V", "family" : "Fullerton", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Clin Nutr", "edition" : "2007/08/09", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2007" ] ] }, "language" : "eng", "page" : "373-381", "title" : "Consumption of fat-free fluid milk after resistance exercise promotes greater lean mass accretion than does consumption of soy or carbohydrate in young, novice, male weightlifters", "type" : "article-journal", "volume" : "86" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[47]", "plainTextFormattedCitation" : "[47]", "previouslyFormattedCitation" : "[47]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[47] are potentially a reflection of the higher DIAAS of whey and casein protein as compared to soy protein. Importantly, casein and whey have higher leucine contents than soy, let alone a number of other essential amino acids. This is particularly important as data from our own laboratory has demonstrated that increasing the leucine concentration of a low protein mixed macronutrient beverage rescues rates of postprandial MPS to those seen with higher protein contents ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/ajcn.113.068775", "ISBN" : "0002-9165", "ISSN" : "00029165", "PMID" : "24284442", "abstract" : "BACKGROUND: Leucine is a key amino acid involved in the regulation of skeletal muscle protein synthesis. OBJECTIVE: We assessed the effect of the supplementation of a lower-protein mixed macronutrient beverage with varying doses of leucine or a mixture of branched chain amino acids (BCAAs) on myofibrillar protein synthesis (MPS) at rest and after exercise. DESIGN: In a parallel group design, 40 men (21 \u00b1 1 y) completed unilateral knee-extensor resistance exercise before the ingestion of 25 g whey protein (W25) (3.0 g leucine), 6.25 g whey protein (W6) (0.75g leucine), 6.25 g whey protein supplemented with leucine to 3.0 g total leucine (W6+Low-Leu), 6.25 g whey protein supplemented with leucine to 5.0 g total leucine (W6+High-Leu), or 6.25 g whey protein supplemented with leucine, isoleucine, and valine to 5.0 g total leucine. A primed continuous infusion of l-[ring-(13)C6] phenylalanine with serial muscle biopsies was used to measure MPS under baseline fasted and postprandial conditions in both a rested (response to feeding) and exercised (response to combined feeding and resistance exercise) leg. RESULTS: The area under the blood leucine curve was greatest for the W6+High-Leu group compared with the W6 and W6+Low-Leu groups (P < 0.001). In the postprandial period, rates of MPS were increased above baseline over 0-1.5 h in all treatments. Over 1.5-4.5 h, MPS remained increased above baseline after all treatments but was greatest after W25 (\u223c267%) and W6+High-Leu (\u223c220%) treatments (P = 0.002). CONCLUSIONS: A low-protein (6.25 g) mixed macronutrient beverage can be as effective as a high-protein dose (25 g) at stimulating increased MPS rates when supplemented with a high (5.0 g total leucine) amount of leucine. These results have important implications for formulations of protein beverages designed to enhance muscle anabolism. This trial was registered at as NCT 1530646.", "author" : [ { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Donato", "given" : "Danielle M.", "non-dropping-particle" : "Di", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hector", "given" : "Amy J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Stellingwerff", "given" : "Trent", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breuille", "given" : "Denis", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Offord", "given" : "Elizabeth a.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American Journal of Clinical Nutrition", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2014" ] ] }, "page" : "276-286", "title" : "Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men: A double-blind, randomized trial1-3", "type" : "article-journal", "volume" : "99" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[48]", "plainTextFormattedCitation" : "[48]", "previouslyFormattedCitation" : "[48]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[48]. Moreover, leucine is a key trigger of the mechanistic target of rapamycin complex 1 (mTORC1), a 280 kDa serine/threonine kinase known to activate key translation initiation factors involved in MPS ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2012.228833 jphysiol.2012.228833 [pii]", "ISBN" : "1469-7793 (Electronic) 0022-3751 (Linking)", "ISSN" : "1469-7793", "PMID" : "22451437", "abstract" : "Leucine is a nutrient regulator of muscle protein synthesis by activating mTOR and possibly other proteins in this pathway. The purpose of this study was to examine the role of leucine in the regulation of human myofibrillar protein synthesis (MPS). Twenty-four males completed an acute bout of unilateral resistance exercise prior to consuming either: a dose (25 g) of whey protein (WHEY); 6.25 g whey protein with total leucine equivalent to WHEY (LEU); or 6.25 g whey protein with total essential amino acids (EAAs) equivalent to WHEY for all EAAs except leucine (EAA-LEU). Measures of MPS, signalling through mTOR, and amino acid transporter (AAT) mRNA abundance were made while fasted (FAST), and following feeding under rested (FED) and post-exercise (EX-FED) conditions. Leucinaemia was equivalent between WHEY and LEU and elevated compared to EAA-LEU (P=0.001). MPS was increased above FAST at 1-3 h post-exercise in both FED (P <0.001) and EX-FED (P <0.001) conditions with no treatment effect.At 3-5 h, only WHEY remained significantly elevated above FAST in EX-FED(WHEY 184% vs. LEU 55% and EAA-LEU 35%; P =0.036). AAT mRNA abundance was increased above FAST after feeding and exercise with no effect of leucinaemia. In summary, a low dose of whey protein supplemented with leucine or all other essential amino acids was as effective as a complete protein (WHEY) in stimulating postprandial MPS; however only WHEY was able to sustain increased rates of MPS post-exercise and may therefore be most suited to increase exercise-induced muscle protein accretion.", "author" : [ { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Philp", "given" : "Andrew", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Marcotte", "given" : "George R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baar", "given" : "Keith", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Physiol", "edition" : "2012/03/28", "id" : "ITEM-1", "issue" : "Pt 11", "issued" : { "date-parts" : [ [ "2012", "6", "1" ] ] }, "language" : "eng", "note" : "From Duplicate 2 ( ", "page" : "2751-2765", "title" : "Supplementation of a suboptimal protein dose with leucine or essential amino acids: effects on myofibrillar protein synthesis at rest and following resistance exercise in men", "type" : "article-journal", "volume" : "590" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[49]", "plainTextFormattedCitation" : "[49]", "previouslyFormattedCitation" : "[49]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[49].Given that supplementing with higher quality protein is crucial to maximizing lean mass accretion with RT, dosing of protein should also be considered. In healthy young men, ~20 grams of protein is optimal to maximally stimulate MPS following a RE bout. This dosage was determined to be sufficient by Moore and colleagues where they examined the dose-response relationship of MPS and protein consumption ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/ajcn.2008.26401.INTRODUCTION", "ISBN" : "1938-3207 (Electronic) 0002-9165 (Linking)", "PMID" : "19056590", "abstract" : "BACKGROUND: The anabolic effect of resistance exercise is enhanced by the provision of dietary protein. OBJECTIVES: We aimed to determine the ingested protein dose response of muscle (MPS) and albumin protein synthesis (APS) after resistance exercise. In addition, we measured the phosphorylation of candidate signaling proteins thought to regulate acute changes in MPS. DESIGN: Six healthy young men reported to the laboratory on 5 separate occasions to perform an intense bout of leg-based resistance exercise. After exercise, participants consumed, in a randomized order, drinks containing 0, 5, 10, 20, or 40 g whole egg protein. Protein synthesis and whole-body leucine oxidation were measured over 4 h after exercise by a primed constant infusion of [1-(13)C]leucine. RESULTS: MPS displayed a dose response to dietary protein ingestion and was maximally stimulated at 20 g. The phosphorylation of ribosomal protein S6 kinase (Thr(389)), ribosomal protein S6 (Ser(240/244)), and the epsilon-subunit of eukaryotic initiation factor 2B (Ser(539)) were unaffected by protein ingestion. APS increased in a dose-dependent manner and also reached a plateau at 20 g ingested protein. Leucine oxidation was significantly increased after 20 and 40 g protein were ingested. CONCLUSIONS: Ingestion of 20 g intact protein is sufficient to maximally stimulate MPS and APS after resistance exercise. Phosphorylation of candidate signaling proteins was not enhanced with any dose of protein ingested, which suggested that the stimulation of MPS after resistance exercise may be related to amino acid availability. Finally, dietary protein consumed after exercise in excess of the rate at which it can be incorporated into tissue protein stimulates irreversible oxidation.", "author" : [ { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Robinson", "given" : "Meghann J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fry", "given" : "Jessica L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tang", "given" : "Jason E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Glover", "given" : "Elisa I", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilkinson", "given" : "Sarah B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Prior", "given" : "Todd", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tarnopolsky", "given" : "Mark A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Clin Nutr", "edition" : "2008/12/06", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2009" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "161-168", "title" : "Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men", "type" : "article-journal", "volume" : "89" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[33]", "plainTextFormattedCitation" : "[33]", "previouslyFormattedCitation" : "[33]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[33]. Healthy male participants ingested 0, 5, 10, 20 or 40 grams of high quality protein on five separate occasions throughout the study period. Rates of MPS increased in a dose-dependent manner until the dose exceeded 20 grams, after which no significant increase in MPS was detected ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/ajcn.2008.26401.INTRODUCTION", "ISBN" : "1938-3207 (Electronic) 0002-9165 (Linking)", "PMID" : "19056590", "abstract" : "BACKGROUND: The anabolic effect of resistance exercise is enhanced by the provision of dietary protein. OBJECTIVES: We aimed to determine the ingested protein dose response of muscle (MPS) and albumin protein synthesis (APS) after resistance exercise. In addition, we measured the phosphorylation of candidate signaling proteins thought to regulate acute changes in MPS. DESIGN: Six healthy young men reported to the laboratory on 5 separate occasions to perform an intense bout of leg-based resistance exercise. After exercise, participants consumed, in a randomized order, drinks containing 0, 5, 10, 20, or 40 g whole egg protein. Protein synthesis and whole-body leucine oxidation were measured over 4 h after exercise by a primed constant infusion of [1-(13)C]leucine. RESULTS: MPS displayed a dose response to dietary protein ingestion and was maximally stimulated at 20 g. The phosphorylation of ribosomal protein S6 kinase (Thr(389)), ribosomal protein S6 (Ser(240/244)), and the epsilon-subunit of eukaryotic initiation factor 2B (Ser(539)) were unaffected by protein ingestion. APS increased in a dose-dependent manner and also reached a plateau at 20 g ingested protein. Leucine oxidation was significantly increased after 20 and 40 g protein were ingested. CONCLUSIONS: Ingestion of 20 g intact protein is sufficient to maximally stimulate MPS and APS after resistance exercise. Phosphorylation of candidate signaling proteins was not enhanced with any dose of protein ingested, which suggested that the stimulation of MPS after resistance exercise may be related to amino acid availability. Finally, dietary protein consumed after exercise in excess of the rate at which it can be incorporated into tissue protein stimulates irreversible oxidation.", "author" : [ { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Robinson", "given" : "Meghann J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fry", "given" : "Jessica L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tang", "given" : "Jason E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Glover", "given" : "Elisa I", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilkinson", "given" : "Sarah B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Prior", "given" : "Todd", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tarnopolsky", "given" : "Mark A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Am J Clin Nutr", "edition" : "2008/12/06", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2009" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "161-168", "title" : "Ingested protein dose response of muscle and albumin protein synthesis after resistance exercise in young men", "type" : "article-journal", "volume" : "89" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[33]", "plainTextFormattedCitation" : "[33]", "previouslyFormattedCitation" : "[33]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[33]. This graded response of MPS to lower doses of protein is also in agreement with the findings of Tipton and colleagues who observed a similar increase in post RE net amino acid balance following the ingestion of 21 grams and 40 grams of high quality protein ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/ajcn.112.055517", "ISSN" : "00029165", "PMID" : "24257722", "abstract" : "Background: The intake of whey, compared with casein and soy protein intakes, stimulates a greater acute response of muscle protein synthesis (MPS) to protein ingestion in rested and exercised muscle. Objective: We characterized the dose-response relation of postab- sorptive rates of myofibrillar MPS to increasing amounts of whey protein at rest and after exercise in resistance-trained, young men. Design: Volunteers (n = 48) consumed a standardized, high-protein (0.54 g/kg body mass) breakfast. Three hours later, a bout of uni- lateral exercise (8 3 10 leg presses and leg extensions; 80% one- repetition maximum) was performed. Volunteers ingested 0, 10, 20, or 40 g whey protein isolate immediately (w10 min) after exercise. Postabsorptive rates of myofibrillar MPS and whole-body rates of phenylalanine oxidation and urea production were measured over a 4-h postdrink period by continuous tracer infusion of labeled [13C6] phenylalanine and [15N2] urea. Results: Myofibrillar MPS (6SD) increased (P , 0.05) above 0 g whey protein (0.041 6 0.015%/h) by 49% and 56% with the in- gestion of 20 and 40 g whey protein, respectively, whereas no additional stimulation was observed with 10 g whey protein (P . 0.05). Rates of phenylalanine oxidation and urea production in- creased with the ingestion of 40 g whey protein. Conclusions: A 20-g dose of whey protein is sufficient for the maximal stimulation of postabsorptive rates of myofibrillar MPS in rested and exercised muscle ofw80-kg resistance-trained, young men. A dose of whey protein.20 g stimulates amino acid oxidation and ureagenesis. This", "author" : [ { "dropping-particle" : "", "family" : "Witard", "given" : "Oliver C.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Jackman", "given" : "Sarah R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Smith", "given" : "Kenneth", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Selby", "given" : "Anna", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tipton", "given" : "Kevin D.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American Journal of Clinical Nutrition", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2014" ] ] }, "page" : "86-95", "title" : "Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise", "type" : "article-journal", "volume" : "99" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[50]", "plainTextFormattedCitation" : "[50]", "previouslyFormattedCitation" : "[50]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[50].Thus, it is evident that protein quality, supplement dose, and supplement timing should be considered when aiming to capitalize on the anabolic response of RE to feeding.IVMeasurement of Skeletal Muscle HypertrophySkeletal muscle hypertrophy, due to RT is postulated to occur as the result of summed periods of repeated acute exercise-induced increases in MPS followed by protein consumption. Though increases in strength are attainable without changes in muscle CSA, increases in muscle hypertrophy are crucial to sustain and/or perpetuate changes in muscle strength as RT progresses. Previously, reliable measurements for assessing changes in muscle hypertrophy were not widely available and thus strength was often used as a proxy measure ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Delorme", "given" : "Thomas L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Schwab", "given" : "Robert S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Watkins", "given" : "Arthur L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Bone & Joint Surgery", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "1948" ] ] }, "page" : "834-847", "title" : "The response of the quadriceps femoris to progressive resistance exercises in poliomyelitic patients", "type" : "article-journal", "volume" : "30" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Moritani", "given" : "T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "DeVries", "given" : "Herbert A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American Journal of Physical Medicine", "id" : "ITEM-2", "issue" : "3", "issued" : { "date-parts" : [ [ "1979" ] ] }, "page" : "115-130", "title" : "Neural factors versus hypertrophy in the time course of muscle strength gain", "type" : "article-journal", "volume" : "58" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[8,14]", "plainTextFormattedCitation" : "[8,14]", "previouslyFormattedCitation" : "[8,14]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[8,14]. For example, in a series of studies by Berger et al. the aim was to determine the optimum prescription for RE with strength remaining the primary outcome measure ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1080/10671188.1962.10616460", "ISSN" : "1067-1188", "author" : [ { "dropping-particle" : "", "family" : "Berger", "given" : "Richard A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Research Quarterly. American Association for Health, Physical Education and Recreation", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "1962", "10", "1" ] ] }, "note" : "doi: 10.1080/10671188.1962.10616460", "page" : "334-338", "publisher" : "Routledge", "title" : "Optimum Repetitions for the Development of Strength", "type" : "article-journal", "volume" : "33" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[51]", "plainTextFormattedCitation" : "[51]", "previouslyFormattedCitation" : "[51]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[51]. For example, in 1962 Berger conducted a 12-week randomized trial in an attempt to determine the optimal number of sets, repetitions, and frequency of RE to increase muscular strength. He determined that 3 sets of 6 repetitions per set, 3 times per week was the most effective way to maximize bench press strength by comparing 6 different exercise regimens ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1080/10671188.1962.10616460", "ISSN" : "1067-1188", "author" : [ { "dropping-particle" : "", "family" : "Berger", "given" : "Richard A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Research Quarterly. American Association for Health, Physical Education and Recreation", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "1962", "10", "1" ] ] }, "note" : "doi: 10.1080/10671188.1962.10616460", "page" : "334-338", "publisher" : "Routledge", "title" : "Optimum Repetitions for the Development of Strength", "type" : "article-journal", "volume" : "33" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[51]", "plainTextFormattedCitation" : "[51]", "previouslyFormattedCitation" : "[51]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[51]. Although the sample size was not what one would consider valid (one participant per exercise group), the results are nonetheless similar to those that are prescribed to this day when individuals are aiming for strength gains. It has only been more recently that changes in body composition as a result of RE have become a major area of study. In 1980, MacDougall ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "0301-5548 (Print)", "abstract" : "Seven healthy male subjects were studied under control conditions and following 5-6 months of heavy resistance training and 5-6 weeks of immobilization in elbow casts. Cross-sectional fibre areas and nuclei-to-fibre ratios were calculated from cryostat sections of needle biopsies taken from triceps brachii. Training resulted in a 98% increase in maximal elbow extension strength as measured by a Cybex dynamometer, while immobilization resulted in a 41% decrease in strength. Both fast twitch (FT) and slow twitch (ST) fibre areas increased significantly with training by 39% and 31%, respectively. Immobilization resulted in significant decreases in fibre area by 33% for FT and 25% for ST fibres. The observed nuclei-to-fibre ratio was 10% greater following the training programme. However, this change was non-significant. There was also a non-significant correlation between the magnitude of the changes in fibre size and the changes in maximal strength following either training or immobilization.", "author" : [ { "dropping-particle" : "", "family" : "Macdougall", "given" : "J D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Elder", "given" : "G C B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Sale", "given" : "D G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moroz", "given" : "J R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Sutton", "given" : "J R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1980" ] ] }, "page" : "25-34", "title" : "Effects of Strength Training and Immobilization on Human Muscle Fibres", "type" : "article-journal", "volume" : "43" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[52]", "plainTextFormattedCitation" : "[52]", "previouslyFormattedCitation" : "[52]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[52] and colleagues investigated the effects of chronic RE followed by immobilization or vice versa to examine strength and lean mass changed in healthy young males. Not surprisingly, fast and slow twitch fiber CSA increased with RE and decreased with immobilization as was determined by the measurement of muscle fibers. Similarly, strength, which was measured by maximum voluntary isometric contraction, varied as a function of CSA change ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "0301-5548 (Print)", "abstract" : "Seven healthy male subjects were studied under control conditions and following 5-6 months of heavy resistance training and 5-6 weeks of immobilization in elbow casts. Cross-sectional fibre areas and nuclei-to-fibre ratios were calculated from cryostat sections of needle biopsies taken from triceps brachii. Training resulted in a 98% increase in maximal elbow extension strength as measured by a Cybex dynamometer, while immobilization resulted in a 41% decrease in strength. Both fast twitch (FT) and slow twitch (ST) fibre areas increased significantly with training by 39% and 31%, respectively. Immobilization resulted in significant decreases in fibre area by 33% for FT and 25% for ST fibres. The observed nuclei-to-fibre ratio was 10% greater following the training programme. However, this change was non-significant. There was also a non-significant correlation between the magnitude of the changes in fibre size and the changes in maximal strength following either training or immobilization.", "author" : [ { "dropping-particle" : "", "family" : "Macdougall", "given" : "J D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Elder", "given" : "G C B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Sale", "given" : "D G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moroz", "given" : "J R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Sutton", "given" : "J R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1980" ] ] }, "page" : "25-34", "title" : "Effects of Strength Training and Immobilization on Human Muscle Fibres", "type" : "article-journal", "volume" : "43" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[52]", "plainTextFormattedCitation" : "[52]", "previouslyFormattedCitation" : "[52]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[52]. Therefore it is clear that muscle CSA mediates changes in muscle strength in young adults and as such if a goal of a RT program is to increase strength by a substantial amount, focusing on strategies to enhance muscular hypertrophy are of the utmost importance. Various techniques have been adopted to evaluate changes in muscle hypertrophy. Each has differing sensitivities to detect change and also to discriminate between tissue types. Previous rudimentary assessments such as measurement of muscle girth ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Delorme", "given" : "Thomas L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Schwab", "given" : "Robert S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Watkins", "given" : "Arthur L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Bone & Joint Surgery", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "1948" ] ] }, "page" : "834-847", "title" : "The response of the quadriceps femoris to progressive resistance exercises in poliomyelitic patients", "type" : "article-journal", "volume" : "30" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[8]", "plainTextFormattedCitation" : "[8]", "previouslyFormattedCitation" : "[8]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[8] have been replaced by advanced imaging techniques which can be used to evaluate single muscle, muscle fibre, or whole body changes. Currently, Dual-Energy X-ray Absorptiometry (DXA) is the most widely used method to determine changes in whole body lean mass. The DXA method uses two low energy x-rays and their relative attenuation by body tissues to quantify body tissues into a 3 compartment model (see Figure II below), but is primarily aimed at measuring bone mineral content and density (the main purpose of the DXA machine), fat content, and fat- and bone-free (i.e., lean) content. Fat- and bone-free mass is a proxy for lean mass and when this DXA-derived body compartment increases with RT it is assumed to represent growth of muscle. The major disadvantage of the DXA for use as a body composition measure is its lack of sensitivity to determine smaller changes in lean mass and also that it cannot examine the compartments of a single muscle; however, it can be used to analyze muscle by groups in the body ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1249/MSS.0b013e31826c9cfd", "ISBN" : "0195-9131", "ISSN" : "01959131", "PMID" : "22895377", "abstract" : "PURPOSE: Dual-energy x-ray absorptiometry (DXA) is rapidly becoming more accessible and popular as a technique to monitor body composition, especially in athletic populations. This study investigates the reliability of DXA in measuring body composition of active individuals, specifically to ascertain biological variability associated with two different types of exercise under free-living conditions in active individuals.\\n\\nMETHODS: Well-trained individuals (27 strength-trained male subjects, 14 female cyclists, and 14 male cyclists) underwent three whole-body DXA scans over a 1-d period: in the morning after an overnight fast, approximately 5 min later after repositioning on the scanning bed, and shortly after a self-chosen exercise session (resistance training or cycling). Subjects were allowed to consume food and fluid ad libitum before and during exercise as per their usual practices. Magnitude of typical (standard) errors of measurement and changes in the mean of DXA measures were assessed by standardization.\\n\\nRESULTS: Exercise and its related practices of fluid and food intake are associated with changes in the mean estimates of total and regional body composition that range from trivial to small but substantial. An exercise session also increases the typical error of measurement of these characteristics by approximately 10%.\\n\\nCONCLUSION: The easiest and most practical way to minimize the biological \"noise\" associated with undertaking a DXA scan is to have subjects fasted and rested before measurement. Until sufficient data on the smallest important effect are available, both biological and technical \"noises\" should be minimized so that any small but potentially \"real\" changes can be confidently detected.", "author" : [ { "dropping-particle" : "", "family" : "Nana", "given" : "Alisa", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Slater", "given" : "Gary J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hopkins", "given" : "Will G.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burke", "given" : "Louise M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and Science in Sports and Exercise", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2013" ] ] }, "page" : "178-185", "title" : "Effects of exercise sessions on DXA measurements of body composition in active people", "type" : "article-journal", "volume" : "45" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[53]", "plainTextFormattedCitation" : "[53]", "previouslyFormattedCitation" : "[53]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[53]. Muscle fibre CSA measured using histochemical approaches is another way in which hypertrophy can be assessed. As opposed to a whole body estimate, muscle fibre CSA change is indicative only of the muscle fibre. In this method, a muscle biopsy sample is fixed, sectioned, mounted on a slide and histologically stained, usually for fiber type, to derive area. The slides are then digitally photographed and quantified, and the change in CSA of varying fiber types can be compared following an intervention involving hypertrophy or atrophy of the muscle fibers ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.01147.2009", "ISBN" : "1522-1601 (Electronic)\\r0161-7567 (Linking)", "ISSN" : "8750-7587", "PMID" : "19910330", "abstract" : "The aim of our study was to determine whether resistance exercise-induced elevations in endogenous hormones enhance muscle strength and hypertrophy with training. Twelve healthy young men (21.8 +/- 1.2 yr, body mass index = 23.1 +/- 0.6 kg/m(2)) trained their elbow flexors independently for 15 wk on separate days and under different hormonal milieu. In one training condition, participants performed isolated arm curl exercise designed to maintain basal hormone concentrations (low hormone, LH); in the other training condition, participants performed identical arm exercise to the LH condition followed immediately by a high volume of leg resistance exercise to elicit a large increase in endogenous hormones (high hormone, HH). There was no elevation in serum growth hormone (GH), insulin-like growth factor (IGF-1), or testosterone after the LH protocol but significant (P < 0.001) elevations in these hormones immediately and 15 and 30 min after the HH protocol. The hormone responses elicited by each respective exercise protocol late in the training period were similar to the response elicited early in the training period, indicating that a divergent postexercise hormone response was maintained over the training period. Muscle cross-sectional area (CSA) increased by 12% in LH and 10% in HH (P < 0.001) with no difference between conditions (condition x training interaction, P = 0.25). Similarly, type I (P < 0.01) and type II (P < 0.001) muscle fiber CSA increased with training with no effect of hormone elevation in the HH condition. Strength increased in both arms, but the increase was not different between the LH and HH conditions. We conclude that exposure of loaded muscle to acute exercise-induced elevations in endogenous anabolic hormones enhances neither muscle hypertrophy nor strength with resistance training in young men.", "author" : [ { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tang", "given" : "Jason E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staples", "given" : "Aaron W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Holwerda", "given" : "Andrew M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of applied physiology (Bethesda, Md. : 1985)", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2009" ] ] }, "page" : "60-67", "title" : "Elevations in ostensibly anabolic hormones with resistance exercise enhance neither training-induced muscle hypertrophy nor strength of the elbow flexors.", "type" : "article-journal", "volume" : "108" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[54]", "plainTextFormattedCitation" : "[54]", "previouslyFormattedCitation" : "[54]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[54]. The disadvantage to this approach is that the mounted image is a sample of only a small portion of the muscle biopsied and thus may not be representative of changes occurring elsewhere in the body. A risk also exists when assessing muscle fibre CSA in that fibres that are not completely perpendicular to the cutting plain of the cryotome resulting in obliquely oriented fibres that are larger than they would normally be. Nonetheless, problems with fibre orientation can be corrected by remounting and re-sectioning the tissue to obtain a more accurate fibre CSA. The gold standard for measuring whole muscle hypertrophy is with magnetic resonance imaging (MRI). Using MRI involves capturing high-resolution cross-sectional images of the desired muscle group and the compartments of muscle, fat, and bone can be determined using grey-scale algorithms using image-processing software. Knowing the image width, sequential cross-sectional images can then be used to calculate muscle volume resulting in indications of changes in size in 3 dimensions ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6]. The only major disadvantage of the use of MRI as a body composition tool is that in many instances in which multiple assessments are required, it is financially untenable. As a result, many scientists employ other approaches to measure, or infer, changes in skeletal muscle size. For example, ultrasound has also more recently been employed for use of evaluating muscle thickness, as a proxy measure of muscle hypertrophy, as it is non-invasive and low cost ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Weiss", "given" : "Lawrence W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Coney", "given" : "Harvey D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Clark", "given" : "Frank C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Orthopaedic & Sports Physical Therapy", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2000" ] ] }, "page" : "143-148", "title" : "Gross Measuresof Exercise-induced Muscular Hypertrophy", "type" : "article-journal", "volume" : "30" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[55]", "plainTextFormattedCitation" : "[55]", "previouslyFormattedCitation" : "[55]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[55]. However, the benefits of ultrasound-measured muscle thickness are balanced by a method that has lower reproducibility, as it is highly dependent on the skill of the operator, sensitive to the position of the limb or segment, and the pressure applied to the probe. Muscle thickness also yields a one-dimensional image of the muscle and therefore it is not sensitive to three-dimensional changes in muscle morphology ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s004210050027", "ISBN" : "1439-6319 (Print)", "ISSN" : "03015548", "PMID" : "10638374", "abstract" : "The purpose of this study was to investigate the time course of skeletal muscle adaptations resulting from high-intensity, upper and lower body dynamic resistance training (WT). A group of 17 men and 20 women were recruited for WT, and 6 men and 7 women served as a control group. The WT group performed six dynamic resistance exercises to fatigue using 8-12 repetition maximum (RM). The subjects trained 3 days a week for 12 weeks. One-RM knee extension (KE) and chest press (CP) exercises were measured at baseline and at weeks 2, 4, 6, 8, and 12 for the WT group. Muscle thickness (MTH) was measured by ultrasound at eight anatomical sites. One-RM CP and KE strength had increased significantly at week 4 for the female WT group. For the men in the WT group, 1 RM had increased significantly at week 2 for KE and at week 6 for CP. The mean relative increases in KE and CP strength were 19% and 19% for the men and 19% and 27% for the women, respectively, after 12 weeks of WT. Resistance training elicited a significant increase in MTH of the chest and triceps muscles at week 6 in both sexes. There were non-significant trends for increases in quadriceps MTH for the WT groups. The relative increases in upper and lower body MTH were 12%-21% and 7%-9% in the men and 10%-31% and 7%-8% in the women respectively, after 12 weeks of WT. These results would suggest that increases in MTH in the upper body are greater and occur earlier compared to the lower extremity, during the first 12 weeks of a total body WT programme. The time-course and proportions of the increase in strength and MTH were similar for both the men and the women.", "author" : [ { "dropping-particle" : "", "family" : "Abe", "given" : "T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "V", "family" : "DeHoyos", "given" : "D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pollock", "given" : "M L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Garzarella", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2000" ] ] }, "page" : "174-180", "title" : "Time course for strength and muscle thickness changes following upper and lower body resistance training in men and women.", "type" : "article-journal", "volume" : "81" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1007/s00421-003-0974-4", "ISBN" : "0042100309744", "ISSN" : "14396319", "PMID" : "14569399", "abstract" : "This study aimed to investigate the accuracy of estimating the volume of limb muscles (MV) using ultrasonographic muscle thickness (MT) measurements. The MT and MV of each of elbow flexors and extensors, knee extensors and ankle plantar flexors were determined from a single ultrasonographic image and multiple magnetic resonance imaging (MRI) scans, respectively, in 27 healthy men (23-40 years of age) who were allocated to validation ( n=14) and cross-validation groups ( n=13). In the validation group, simple and multiple regression equations using MT and a set of MT and limb length, respectively, as independent variables were derived to estimate the MV measured by MRI. However, only the multiple regression equations were cross-validated, and so the prediction equations with r(2) of 0.787-0.884 and the standard error of estimate of 22.1 cm(3) (7.3%) for the elbow flexors to 198.5 cm(3) (11.1%) for the knee extensors were developed using the pooled data. This approach did not induce significant systematic error in any muscle group, with no significant difference in the accuracy of estimating MV between muscle groups. In the multiple regression equations, the relative contribution of MT for predicting MV varied from 41.9% for the knee extensors to 70.4% for the elbow flexors. Thus, ultrasonographic MT measurement was a good predictor of MV when combined with limb length. For predicting MV, however, the unsuitability of a simple equation using MT only and the difference between muscle groups in the relative contribution of MT in multiple regression equations indicated a need for further research on the limb site selected and muscle analyzed for MT measurement.", "author" : [ { "dropping-particle" : "", "family" : "Miyatani", "given" : "Masae", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kanehisa", "given" : "Hiroaki", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ito", "given" : "Masamitsu", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kawakami", "given" : "Yasuo", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Eukunaga", "given" : "Tetsuo", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European Journal of Applied Physiology", "id" : "ITEM-2", "issued" : { "date-parts" : [ [ "2004" ] ] }, "page" : "264-272", "title" : "The accuracy of volume estimates using ultrasound muscle thickness measurements in different muscle groups", "type" : "article-journal", "volume" : "91" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[56,57]", "plainTextFormattedCitation" : "[56,57]", "previouslyFormattedCitation" : "[56,57]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[56,57]. It is clear that all of the aforementioned methods have various advantages and disadvantages depending on the muscle or body composition variable being studied though over all, DXA is the most widely used to determine whole body composition (Figure ii). -3429003657600Figure ii. Compartments represented in the 2 and 3 compartment models of body composition. FFM; Fat free mass, FBFM; Fat bone-free mass.0Figure ii. Compartments represented in the 2 and 3 compartment models of body composition. FFM; Fat free mass, FBFM; Fat bone-free mass.685800-342900V Resistance Training RecommendationsThe first recommendations for inducing skeletal muscle hypertrophy with the goal of increasing strength and performance were documented in a seminal paper by Delorme in 1945 ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Delorme", "given" : "Thomas L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Bone & Joint Surgery", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "1945" ] ] }, "page" : "645-667", "title" : "Restoration of muscle power by heavy-resistance exercises", "type" : "article-journal", "volume" : "27" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[11]", "plainTextFormattedCitation" : "[11]", "previouslyFormattedCitation" : "[11]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[11]. Delorme studied the effects of varying protocols of RT to affect the quadriceps function in soldiers who were rehabilitating after World War 2. From his findings he concluded that low repetition, higher resistance exercises should be used to produce ‘favourable’ changes in muscle strength while high repetition, low resistance exercises should be used to produce muscular endurance. Furthermore, the author concluded that “each of these two types of exercise is incapable of producing results obtained by the other” ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Delorme", "given" : "Thomas L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of Bone & Joint Surgery", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "1945" ] ] }, "page" : "645-667", "title" : "Restoration of muscle power by heavy-resistance exercises", "type" : "article-journal", "volume" : "27" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[11]", "plainTextFormattedCitation" : "[11]", "previouslyFormattedCitation" : "[11]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[11]. Although 70 years have passed since the work of Delorme, the accepted protocols for promoting changes in muscle phenotype remain remarkably unchanged. The most recent position stand from the American College of Sports Medicine likely represents one of the most widely accepted and implemented guidelines used in the development of resistance training programs, aiming to increase muscle mass ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1249/MSS.0b013e3181915670", "ISSN" : "1530-0315", "PMID" : "19204579", "abstract" : "In order to stimulate further adaptation toward specific training goals, progressive resistance training (RT) protocols are necessary. The optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single- and multiple-joint exercises. In addition, it is recommended that strength programs sequence exercises to optimize the preservation of exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher-intensity before lower-intensity exercises). For novice (untrained individuals with no RT experience or who have not trained for several years) training, it is recommended that loads correspond to a repetition range of an 8-12 repetition maximum (RM). For intermediate (individuals with approximately 6 months of consistent RT experience) to advanced (individuals with years of RT experience) training, it is recommended that individuals use a wider loading range from 1 to 12 RM in a periodized fashion with eventual emphasis on heavy loading (1-6 RM) using 3- to 5-min rest periods between sets performed at a moderate contraction velocity (1-2 s CON; 1-2 s ECC). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d x wk(-1) for novice training, 3-4 d x wk(-1) for intermediate training, and 4-5 d x wk(-1) for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training and 2) use of light loads (0-60% of 1 RM for lower body exercises; 30-60% of 1 RM for upper body exercises) performed at a fast contraction velocity with 3-5 min of rest between sets for multiple sets per exercise (three to five sets). It is also recommended that emphasis be placed on multiple-joint exercises especially those involving the total body. For local muscular endurance t\u2026", "author" : [ { "dropping-particle" : "", "family" : "ASM", "given" : "", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and science in sports and exercise", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2009", "3" ] ] }, "page" : "687-708", "title" : "American College of Sports Medicine position stand. Progression models in resistance training for healthy adults.", "type" : "article-journal", "volume" : "41" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[58]", "plainTextFormattedCitation" : "[58]", "previouslyFormattedCitation" : "[58]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[58]. The 2002 ACSM position stand entitled Progression models in resistance training for healthy adults states that the optimum ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1249/MSS.0b013e3181915670", "ISBN" : "0195-9131 (Print)", "ISSN" : "1530-0315", "PMID" : "11828249", "abstract" : "In order to stimulate further adaptation toward a specific training goal(s), progression in the type of resistance training protocol used is necessary. The optimal characteristics of strength-specific programs include the use of both concentric and eccentric muscle actions and the performance of both single- and multiple-joint exercises. It is also recommended that the strength program sequence exercises to optimize the quality of the exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher intensity before lower intensity exer- cises). For initial resistances, it is recommended that loads corresponding to 8\u201312 repetition maximum (RM) be used in novice training. For intermediate to advanced training, it is recommended that individuals use a wider loading range, from 1\u201312 RM in a periodized fashion, with eventual emphasis on heavy loading (1\u20136 RM) using at least 3-min rest periods between sets performed at a moderate contraction velocity (1\u20132 s concentric, 1\u20132 s eccen- tric). When training at a specific RM load, it is recommended that 2\u201310% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommen- dation for training frequency is 2\u20133 d\u00b7wk\ue0011 for novice and intermediate training and 4\u20135 d\u00b7wk\ue0011 for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1\u201312 RMbe used in periodized fashion, with emphasis on the 6\u201312RMzone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Pro- gression in power training entails two general loading strategies: 1) strength training, and 2) use of light loads (30\u201360% of 1 RM) performed at a fast contraction velocity with 2\u20133 min of rest between sets for multiple sets per exercise. It is also recommended that emphasis be placed on multiple-joint exercises, especially those involving the total body. For local muscular endur- ance training, it is recommended that light to moderate loads (40\u201360% of 1 RM) be performed for high repetitions (\ue00215) using short rest periods (\ue00390 s). In the interpretation of this position stand, as with prior ones, the recommen- dations should be viewed in context of the individual\u2019s target goals, physical capacity\u2026", "container-title" : "Medicine & Science in Sports & Exercise", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2002" ] ] }, "page" : "364-380", "title" : "Progression models in resistance training for healthy adults", "type" : "article-journal", "volume" : "34" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[59]", "plainTextFormattedCitation" : "[59]", "previouslyFormattedCitation" : "[59]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[59] RT program for the increase in muscular hypertrophy involves repetition ranges of 8-12 repetitions per set at a load between 70-85% of maximal strength, which is most often guided by measurement of single-lift maximal strength or 1RM. Additionally, the same position stand suggests a repetition range of 10-25 reps per set at a lighter resistive load as being more favourable for adaptations to promote muscular endurance not unlike what was suggested by Delorme ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1249/MSS.0b013e3181915670", "ISSN" : "1530-0315", "PMID" : "19204579", "abstract" : "In order to stimulate further adaptation toward specific training goals, progressive resistance training (RT) protocols are necessary. The optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single- and multiple-joint exercises. In addition, it is recommended that strength programs sequence exercises to optimize the preservation of exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher-intensity before lower-intensity exercises). For novice (untrained individuals with no RT experience or who have not trained for several years) training, it is recommended that loads correspond to a repetition range of an 8-12 repetition maximum (RM). For intermediate (individuals with approximately 6 months of consistent RT experience) to advanced (individuals with years of RT experience) training, it is recommended that individuals use a wider loading range from 1 to 12 RM in a periodized fashion with eventual emphasis on heavy loading (1-6 RM) using 3- to 5-min rest periods between sets performed at a moderate contraction velocity (1-2 s CON; 1-2 s ECC). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d x wk(-1) for novice training, 3-4 d x wk(-1) for intermediate training, and 4-5 d x wk(-1) for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training and 2) use of light loads (0-60% of 1 RM for lower body exercises; 30-60% of 1 RM for upper body exercises) performed at a fast contraction velocity with 3-5 min of rest between sets for multiple sets per exercise (three to five sets). It is also recommended that emphasis be placed on multiple-joint exercises especially those involving the total body. For local muscular endurance t\u2026", "author" : [ { "dropping-particle" : "", "family" : "ASM", "given" : "", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and science in sports and exercise", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2009", "3" ] ] }, "page" : "687-708", "title" : "American College of Sports Medicine position stand. Progression models in resistance training for healthy adults.", "type" : "article-journal", "volume" : "41" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[58]", "plainTextFormattedCitation" : "[58]", "previouslyFormattedCitation" : "[58]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[58]. It is proposed that a careful reading of the ACSM position stand also implies, as did Delorme, that the goal of muscular strength and muscular endurance are mutually exclusive.The purpose of the most current ACSM position stand (2009) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1249/MSS.0b013e3181915670", "ISSN" : "1530-0315", "PMID" : "19204579", "abstract" : "In order to stimulate further adaptation toward specific training goals, progressive resistance training (RT) protocols are necessary. The optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single- and multiple-joint exercises. In addition, it is recommended that strength programs sequence exercises to optimize the preservation of exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher-intensity before lower-intensity exercises). For novice (untrained individuals with no RT experience or who have not trained for several years) training, it is recommended that loads correspond to a repetition range of an 8-12 repetition maximum (RM). For intermediate (individuals with approximately 6 months of consistent RT experience) to advanced (individuals with years of RT experience) training, it is recommended that individuals use a wider loading range from 1 to 12 RM in a periodized fashion with eventual emphasis on heavy loading (1-6 RM) using 3- to 5-min rest periods between sets performed at a moderate contraction velocity (1-2 s CON; 1-2 s ECC). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d x wk(-1) for novice training, 3-4 d x wk(-1) for intermediate training, and 4-5 d x wk(-1) for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training and 2) use of light loads (0-60% of 1 RM for lower body exercises; 30-60% of 1 RM for upper body exercises) performed at a fast contraction velocity with 3-5 min of rest between sets for multiple sets per exercise (three to five sets). It is also recommended that emphasis be placed on multiple-joint exercises especially those involving the total body. For local muscular endurance t\u2026", "author" : [ { "dropping-particle" : "", "family" : "ASM", "given" : "", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and science in sports and exercise", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2009", "3" ] ] }, "page" : "687-708", "title" : "American College of Sports Medicine position stand. Progression models in resistance training for healthy adults.", "type" : "article-journal", "volume" : "41" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[58]", "plainTextFormattedCitation" : "[58]", "previouslyFormattedCitation" : "[58]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[58] was to include a more robust selection of literature which had been recently developed following the publication of the position stand created in 2002. Upon close examination it is clear that references within the 2009 document detailing the guidelines for optimize hypertrophy contain only a single study supporting the notion that heavier loads are associated with greater hypertrophy ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5]", "plainTextFormattedCitation" : "[5]", "previouslyFormattedCitation" : "[5]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5]. The cited study ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5]", "plainTextFormattedCitation" : "[5]", "previouslyFormattedCitation" : "[5]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5] by Campos et al., detailed the examination of the effects of an 8-week resistance training program on hypertrophy and strength in young, untrained men performing either low repetition (3-5 repetitions/set), intermediate repetition (9-11 repetitions/set) or high repetition (20-28 repetitions/set) whole body exercise. Exercise was performed twice per week for the first 4 weeks and then three times per week for the final 4 weeks of the program. The authors reported that the lower repetition group had the greatest increases in muscular CSA and strength measured by 1RM. While the higher repetition group demonstrated improvements, overall these improvements were not maximally beneficial. It is interesting to note that the groups performing “intermediate” repetitions and “high” repetitions as dictated by study design, are reflective of the suggestions made by the ACSM position stand and when these groups are compared there was no significant difference in the increase in leg extension or squat 1RM. However, strength gains were greater in the low repetition group. Nonetheless, strength gains were attainable based on the recommendations by the ACSM. It is also likely that the groups in this study were too small and thus, the study was underpowered, to show differences between groups ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5]", "plainTextFormattedCitation" : "[5]", "previouslyFormattedCitation" : "[5]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5]. Sample sizes ranged from 7-11 participants per group and it is well documented that the hypertrophic response to RE is highly variable ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1371/journal.pone.0089431", "ISSN" : "19326203", "PMID" : "24586775", "abstract" : "Muscle hypertrophy following resistance training (RT) involves activation of myofibrillar protein synthesis (MPS) to expand the myofibrillar protein pool. The degree of hypertrophy following RT is, however, highly variable and thus we sought to determine the relationship between the acute activation of MPS and RT-induced hypertrophy. We measured MPS and signalling protein activation after the first session of resistance exercise (RE) in untrained men (n = 23) and then examined the relation between MPS with magnetic resonance image determined hypertrophy. To measure MPS, young men (24\u00b11 yr; body mass index = 26.4\u00b10.9 kg\u2022m\u00b2) underwent a primed constant infusion of L-[ring-\u00b9\u00b3C\u2086] phenylalanine to measure MPS at rest, and acutely following their first bout of RE prior to 16 wk of RT. Rates of MPS were increased 235\u00b138% (P<0.001) above rest 60-180 min post-exercise and 184\u00b128% (P = 0.037) 180-360 min post exercise. Quadriceps volume increased 7.9\u00b11.6% (-1.9-24.7%) (P<0.001) after training. There was no correlation between changes in quadriceps muscle volume and acute rates of MPS measured over 1-3 h (r = 0.02), 3-6 h (r = 0.16) or the aggregate 1-6 h post-exercise period (r = 0.10). Hypertrophy after chronic RT was correlated (r = 0.42, P = 0.05) with phosphorylation of 4E-BP1(Thr37/46) at 1 hour post RE. We conclude that acute measures of MPS following an initial exposure to RE in novices are not correlated with muscle hypertrophy following chronic RT.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Parise", "given" : "Gianni", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Bellamy", "given" : "Leeann", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Smith", "given" : "Kenneth", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Atherton", "given" : "Philip J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "PLoS ONE", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "2014" ] ] }, "page" : "1-7", "title" : "Acute post-exercise myofibrillar protein synthesis is not correlated with resistance training-induced muscle hypertrophy in young men", "type" : "article-journal", "volume" : "9" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[60]", "plainTextFormattedCitation" : "[60]", "previouslyFormattedCitation" : "[60]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[60]. 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The optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single- and multiple-joint exercises. In addition, it is recommended that strength programs sequence exercises to optimize the preservation of exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher-intensity before lower-intensity exercises). For novice (untrained individuals with no RT experience or who have not trained for several years) training, it is recommended that loads correspond to a repetition range of an 8-12 repetition maximum (RM). For intermediate (individuals with approximately 6 months of consistent RT experience) to advanced (individuals with years of RT experience) training, it is recommended that individuals use a wider loading range from 1 to 12 RM in a periodized fashion with eventual emphasis on heavy loading (1-6 RM) using 3- to 5-min rest periods between sets performed at a moderate contraction velocity (1-2 s CON; 1-2 s ECC). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d x wk(-1) for novice training, 3-4 d x wk(-1) for intermediate training, and 4-5 d x wk(-1) for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training and 2) use of light loads (0-60% of 1 RM for lower body exercises; 30-60% of 1 RM for upper body exercises) performed at a fast contraction velocity with 3-5 min of rest between sets for multiple sets per exercise (three to five sets). It is also recommended that emphasis be placed on multiple-joint exercises especially those involving the total body. 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Unfortunately, in the position stand, the authors failed to include data from a study performed by Léger and colleagues ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2006.116715", "ISSN" : "0022-3751", "PMID" : "16916907", "abstract" : "Skeletal muscle size is tightly regulated by the synergy between anabolic and catabolic signalling pathways which, in humans, have not been well characterized. Akt has been suggested to play a pivotal role in the regulation of skeletal muscle hypertrophy and atrophy in rodents and cells. Here we measured the amount of phospho-Akt and several of its downstream anabolic targets (glycogen synthase kinase-3beta (GSK-3beta), mTOR, p70(s6k) and 4E-BP1) and catabolic targets (Foxo1, Foxo3, atrogin-1 and MuRF1). All measurements were performed in human quadriceps muscle biopsies taken after 8 weeks of both hypertrophy-stimulating resistance training and atrophy-stimulating de-training. Following resistance training a muscle hypertrophy ( approximately 10%) and an increase in phospho-Akt, phospho-GSK-3beta and phospho-mTOR protein content were observed. This was paralleled by a decrease in Foxo1 nuclear protein content. Following the de-training period a muscle atrophy (5%), relative to the post-training muscle size, a decrease in phospho-Akt and GSK-3beta and an increase in Foxo1 were observed. Atrogin-1 and MuRF1 increased after the hypertrophy and decreased after the atrophy phases. 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Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. 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All measurements were performed in human quadriceps muscle biopsies taken after 8 weeks of both hypertrophy-stimulating resistance training and atrophy-stimulating de-training. Following resistance training a muscle hypertrophy ( approximately 10%) and an increase in phospho-Akt, phospho-GSK-3beta and phospho-mTOR protein content were observed. This was paralleled by a decrease in Foxo1 nuclear protein content. Following the de-training period a muscle atrophy (5%), relative to the post-training muscle size, a decrease in phospho-Akt and GSK-3beta and an increase in Foxo1 were observed. Atrogin-1 and MuRF1 increased after the hypertrophy and decreased after the atrophy phases. We demonstrate, for the first time in human skeletal muscle, that the regulation of Akt and its downstream signalling pathways GSK-3beta, mTOR and Foxo1 are associated with both the skeletal muscle hypertrophy and atrophy processes.", "author" : [ { "dropping-particle" : "", "family" : "L\u00e9ger", "given" : "Bertrand", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cartoni", "given" : "Romain", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Praz", "given" : "Manu", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lamon", "given" : "S\u00e9verine", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "D\u00e9riaz", "given" : "Olivier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Crettenand", "given" : "Antoinette", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Gobelet", "given" : "Charles", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rohmer", "given" : "Paul", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Konzelmann", "given" : "Michel", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luthi", "given" : "Fran\u00e7ois", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Russell", "given" : "Aaron P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-1", "issue" : "Pt 3", "issued" : { "date-parts" : [ [ "2006", "11", "1" ] ] }, "page" : "923-33", "title" : "Akt signalling through GSK-3beta, mTOR and Foxo1 is involved in human skeletal muscle hypertrophy and atrophy.", "type" : "article-journal", "volume" : "576" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[61]", "plainTextFormattedCitation" : "[61]", "previouslyFormattedCitation" : "[61]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[61]. Clearly, the current ACSM position stand lacks clarity and bona fide experimental evidence in regards to their suggested prescriptions for inducing hypertrophy and strength and thus one of the overarching purposes of the current study was to better elucidate the phenotypic changes that occur with RT in subjects engaging in protocols utilizing differing repetition ranges, performed to fatigue.Recommendations for the use of heavy loads during RT to induce muscle hypertrophy have been prescribed despite what I view as there being a sparse supply of evidence that confirms the superiority of this prescription over the use of lighter RE loads. It is important to acknowledge that strength training with heavy loads is effective at increasing muscle CSA when RE is performed over a significant period of time ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/BF02388334", "ISBN" : "1439-6327", "ISSN" : "03015548", "PMID" : "2583179", "abstract" : "Four male subjects aged 23-34 years were studied during 60 days of unilateral strength training and 40 days of detraining. Training was carried out four times a week and consisted of six series of ten maximal isokinetic knee extensions at an angular velocity of 2.09 rad.s-1. At the start and at every 20th day of training and detraining, isometric maximal voluntary contraction (MVC), integrated electromyographic activity (iEMG) and quadriceps muscle cross-sectional area (CSA) assessed at seven fractions of femur length (Lf), by nuclear magnetic resonance imaging, were measured on both trained (T) and untrained (UT) legs. Isokinetic torques at 30 degrees before full knee extension were measured before and at the end of training at: 0, 1.05, 2.09, 3.14, 4.19, 5.24 rad.s-1. After 60 days T leg CSA had increased by 8.5% +/- 1.4% (mean +/- SEM, n = 4, p less than 0.001), iEMG by 42.4% +/- 16.5% (p less than 0.01) and MVC by 20.8% +/- 5.4% (p less than 0.01). Changes during detraining had a similar time course to those of training. No changes in UT leg CSA were observed while iEMG and MVC increased by 24.8% +/- 10% (N.S.) and 8.7% +/- 4.3% (N.S.), respectively. The increase in quadriceps muscle CSA was maximal at 2/10 Lf (12.0% +/- 1.5%, p less than 0.01) and minimal, proximally to the knee, at 8/10 Lf (3.5% +/- 1.2%, N.S.). Preferential hypertrophy of the vastus medialis and intermedius muscles compared to those of the rectus femoris and lateralis muscles was observed.", "author" : [ { "dropping-particle" : "V.", "family" : "Narici", "given" : "M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Roi", "given" : "G. S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Landoni", "given" : "L.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Minetti", "given" : "a. E.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cerretelli", "given" : "P.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European Journal of Applied Physiology and Occupational Physiology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1989" ] ] }, "page" : "310-319", "title" : "Changes in force, cross-sectional area and neural activation during strength training and detraining of the human quadriceps", "type" : "article-journal", "volume" : "59" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1152/japplphysiol.00789.2006", "ISBN" : "8750-7587 (Print)", "ISSN" : "8750-7587", "PMID" : "17053104", "abstract" : "The onset of whole muscle hypertrophy in response to overloading is poorly documented. The purpose of this study was to assess the early changes in muscle size and architecture during a 35-day high-intensity resistance training (RT) program. Seven young healthy volunteers performed bilateral leg extension three times per week on a gravity-independent flywheel ergometer. Cross-sectional area (CSA) in the central (C) and distal (D) regions of the quadriceps femoris (QF), muscle architecture, maximal voluntary contraction (MVC), and electromyographic (EMG) activity were measured before and after 10, 20, and 35 days of RT. By the end of the training period, MVC and EMG activity increased by 38.9 +/- 5.7 and 34.8% +/- 4.7%, respectively. Significant increase in QF CSA (3.5 and 5.2% in the C and D regions, respectively) was observed after 20 days of training, along with a 2.4 +/- 0.7% increase in fascicle length from the 10th day of training. By the end of the 35-day training period, the total increase in QF CSA for regions C and D was 6.5 +/- 1.1 and 7.4 +/- 0.8%, respectively, and fascicle length and pennation angle increased by 9.9 +/- 1.2 and 7.7 +/- 1.3%, respectively. The results show for the first time that changes in muscle size are detectable after only 3 wk of RT and that remodeling of muscle architecture precedes gains in muscle CSA. Muscle hypertrophy seems to contribute to strength gains earlier than previously reported; flywheel training seems particularly effective for inducing these early structural adaptations.", "author" : [ { "dropping-particle" : "", "family" : "Seynnes", "given" : "O R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Boer", "given" : "M", "non-dropping-particle" : "de", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "V", "family" : "Narici", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of applied physiology (Bethesda, Md. : 1985)", "id" : "ITEM-2", "issued" : { "date-parts" : [ [ "2007" ] ] }, "page" : "368-373", "title" : "Early skeletal muscle hypertrophy and architectural changes in response to high-intensity resistance training.", "type" : "article-journal", "volume" : "102" }, "uris" : [ "" ] }, { "id" : "ITEM-3", "itemData" : { "ISBN" : "1365-2362", "ISSN" : "00142972", "PMID" : "6416856", "abstract" : "Seventeen volunteers performed unilateral strength-training of the quadriceps with high-resistance, low-repetition, dynamic exercise, thrice weekly for an average of 5 weeks. Both before and after the training period, bilateral measurements were made of isometric quadriceps strength, quadriceps cross-sectional area (by ultrasound scanning), and thigh circumference. There were no significant changes in the untrained thighs. The trained quadriceps increased their isometric strength by more than they changed their cross-sectional area (mean increments = 15% and 6% respectively). Quadriceps hypertrophy was underestimated by measurements of thigh circumference and could not be predicted from them. We conclude that studies of localized muscle growth require direct measurements of the size of the muscle(s) concerned. Nevertheless, these may still underestimate the improvements in strength produced by high-resistance training.", "author" : [ { "dropping-particle" : "", "family" : "Young", "given" : "a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Stokes", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Round", "given" : "J M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Edwards", "given" : "R H", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of clinical investigation", "id" : "ITEM-3", "issued" : { "date-parts" : [ [ "1983" ] ] }, "page" : "411-417", "title" : "The effect of high-resistance training on the strength and cross-sectional area of the human quadriceps.", "type" : "article-journal", "volume" : "13" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[13,18,62]", "plainTextFormattedCitation" : "[13,18,62]", "previouslyFormattedCitation" : "[13,18,62]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[13,18,62]. Whether heavy loads are superior to lighter loads is still, I would propose, equivocal as the results of a recent meta-analysis would suggest ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Schoenfeld", "given" : "Brad J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilson", "given" : "Jacob M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lowery", "given" : "Ryan P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Krieger", "given" : "James W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "id" : "ITEM-1", "issue" : "00", "issued" : { "date-parts" : [ [ "2014" ] ] }, "page" : "1-10", "title" : "Muscular adaptations in low- versus high-load resistance training : A meta-analysis", "type" : "article-journal", "volume" : "00" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[63]", "plainTextFormattedCitation" : "[63]", "previouslyFormattedCitation" : "[63]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[63]. When comparing the effects of RE load on CSA, it is important to consider the volume of exercise that is performed. Holm et al. used a unilateral model to evaluate the adaptive changes in muscle size with RE loads of either 16% of 1RM for 36 repetitions or 70% of 1RM for 8 repetitions on each leg. Following 12 weeks of training, limbs training with both heavy and light loads demonstrated a significant increase in quadriceps CSA; however, the limbs performing heavier loading showed a 5% greater increase (7.6% increase in the lower rep group and 2.6% in the higher rep) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.90538.2008", "ISBN" : "8750-7587 (Print)", "ISSN" : "8750-7587", "PMID" : "18787090", "abstract" : "Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60 degrees /s. Quadriceps muscle cross-sectional area increased (P < 0.05) 8 +/- 1% and 3 +/- 1% in HL and LL legs, respectively, with a greater gain in HL than LL (P < 0.05). Likewise, 1RM strength increased (P < 0.001) in both legs (HL: 36 +/- 5%, LL: 19 +/- 2%), albeit more so with HL (P < 0.01). Isokinetic 60 degrees /s muscle strength improved by 13 +/- 5% (P < 0.05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.", "author" : [ { "dropping-particle" : "", "family" : "Holm", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Reitelseder", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pedersen", "given" : "T G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Doessing", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Petersen", "given" : "S G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Flyvbjerg", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Andersen", "given" : "J L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aagaard", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kjaer", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Applied Physiology", "id" : "ITEM-1", "issue" : "5", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "1454-1461", "title" : "Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity.", "type" : "article-journal", "volume" : "105" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[64]", "plainTextFormattedCitation" : "[64]", "previouslyFormattedCitation" : "[64]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[64]. Thus upon initial investigation it would appear that heavier RE loads do result in greater hypertrophy if repetition ranges are set to ensure similar workloads and that lighter RE loads are inefficient in attaining similar muscular hypertrophy. Contrary to the ACSM guidelines ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1249/MSS.0b013e3181915670", "ISSN" : "1530-0315", "PMID" : "19204579", "abstract" : "In order to stimulate further adaptation toward specific training goals, progressive resistance training (RT) protocols are necessary. The optimal characteristics of strength-specific programs include the use of concentric (CON), eccentric (ECC), and isometric muscle actions and the performance of bilateral and unilateral single- and multiple-joint exercises. In addition, it is recommended that strength programs sequence exercises to optimize the preservation of exercise intensity (large before small muscle group exercises, multiple-joint exercises before single-joint exercises, and higher-intensity before lower-intensity exercises). For novice (untrained individuals with no RT experience or who have not trained for several years) training, it is recommended that loads correspond to a repetition range of an 8-12 repetition maximum (RM). For intermediate (individuals with approximately 6 months of consistent RT experience) to advanced (individuals with years of RT experience) training, it is recommended that individuals use a wider loading range from 1 to 12 RM in a periodized fashion with eventual emphasis on heavy loading (1-6 RM) using 3- to 5-min rest periods between sets performed at a moderate contraction velocity (1-2 s CON; 1-2 s ECC). When training at a specific RM load, it is recommended that 2-10% increase in load be applied when the individual can perform the current workload for one to two repetitions over the desired number. The recommendation for training frequency is 2-3 d x wk(-1) for novice training, 3-4 d x wk(-1) for intermediate training, and 4-5 d x wk(-1) for advanced training. Similar program designs are recommended for hypertrophy training with respect to exercise selection and frequency. For loading, it is recommended that loads corresponding to 1-12 RM be used in periodized fashion with emphasis on the 6-12 RM zone using 1- to 2-min rest periods between sets at a moderate velocity. Higher volume, multiple-set programs are recommended for maximizing hypertrophy. Progression in power training entails two general loading strategies: 1) strength training and 2) use of light loads (0-60% of 1 RM for lower body exercises; 30-60% of 1 RM for upper body exercises) performed at a fast contraction velocity with 3-5 min of rest between sets for multiple sets per exercise (three to five sets). It is also recommended that emphasis be placed on multiple-joint exercises especially those involving the total body. For local muscular endurance t\u2026", "author" : [ { "dropping-particle" : "", "family" : "ASM", "given" : "", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and science in sports and exercise", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "2009", "3" ] ] }, "page" : "687-708", "title" : "American College of Sports Medicine position stand. Progression models in resistance training for healthy adults.", "type" : "article-journal", "volume" : "41" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[58]", "plainTextFormattedCitation" : "[58]", "previouslyFormattedCitation" : "[58]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[58], it has recently been suggested that repetition-load (exercise load) plays a lesser role in the hypertrophy response so long as volitional fatigue is achieved when lifting with a lighter load ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Schoenfeld", "given" : "Brad J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilson", "given" : "Jacob M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lowery", "given" : "Ryan P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Krieger", "given" : "James W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "id" : "ITEM-1", "issue" : "00", "issued" : { "date-parts" : [ [ "2014" ] ] }, "page" : "1-10", "title" : "Muscular adaptations in low- versus high-load resistance training : A meta-analysis", "type" : "article-journal", "volume" : "00" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[63]", "plainTextFormattedCitation" : "[63]", "previouslyFormattedCitation" : "[63]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[63]. Another example of how lighter loads can result in hypertrophy comes from studies in which blood flow restriction (BFR) has been employed. Using BFR with flow occlusion cuffs, a process that induces the rapid fatiguing of smaller MUs and thus, type I muscle fibres at a low loads resulting in early onset recruitment and fatigue of larger MUs and type II fibres. Results from with the use of this technique have reported similar increases to traditional RE-induced MPS. Fujita and colleagues ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00195.2007", "ISBN" : "8750-7587 (Print)\\r0161-7567 (Linking)", "ISSN" : "8750-7587", "PMID" : "17569770", "abstract" : "Low-intensity resistance exercise training combined with blood flow restriction (REFR) increases muscle size and strength as much as conventional resistance exercise with high loads. However, the cellular mechanism(s) underlying the hypertrophy and strength gains induced by REFR are unknown. We have recently shown that both the mammalian target of rapamycin (mTOR) signaling pathway and muscle protein synthesis (MPS) were stimulated after an acute bout of high-intensity resistance exercise in humans. Therefore, we hypothesized that an acute bout of REFR would enhance mTOR signaling and stimulate MPS. We measured MPS and phosphorylation status of mTOR-associated signaling proteins in six young male subjects. Subjects were studied once during blood flow restriction (REFR, bilateral leg extension exercise at 20% of 1 repetition maximum while a pressure cuff was placed on the proximal end of both thighs and inflated at 200 mmHg) and a second time using the same exercise protocol but without the pressure cuff [control (Ctrl)]. MPS in the vastus lateralis muscle was measured by using stable isotope techniques, and the phosphorylation status of signaling proteins was determined by immunoblotting. Blood lactate, cortisol, and growth hormone were higher following REFR compared with Ctrl (P < 0.05). Ribosomal S6 kinase 1 (S6K1) phosphorylation, a downstream target of mTOR, increased concurrently with a decreased eukaryotic translation elongation factor 2 (eEF2) phosphorylation and a 46% increase in MPS following REFR (P < 0.05). MPS and S6K1 phosphorylation were unchanged in the Ctrl group postexercise. We conclude that the activation of the mTOR signaling pathway appears to be an important cellular mechanism that may help explain the enhanced muscle protein synthesis during REFR.", "author" : [ { "dropping-particle" : "", "family" : "Fujita", "given" : "Satoshi", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Abe", "given" : "Takashi", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Drummond", "given" : "Micah J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cadenas", "given" : "Jerson G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Dreyer", "given" : "Hans C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Sato", "given" : "Yoshiaki", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Volpi", "given" : "Elena", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rasmussen", "given" : "Blake B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of applied physiology (Bethesda, Md. : 1985)", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2007" ] ] }, "page" : "903-910", "title" : "Blood flow restriction during low-intensity resistance exercise increases S6K1 phosphorylation and muscle protein synthesis.", "type" : "article-journal", "volume" : "103" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[65]", "plainTextFormattedCitation" : "[65]", "previouslyFormattedCitation" : "[65]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[65] examined the effects of low-load RE with and without vascular occlusion of the quadriceps. Subjects acted as both intervention and control with a wash out period of three weeks in-between. RE was performed at 20% of 1RM for 30 repetitions and the MPS response was measured 3 hours following exercise. The authors reported that vascular occlusion induced an increase in MPS of 46% while the non-occluded condition yielded no change in MPS ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00195.2007", "ISBN" : "8750-7587 (Print)\\r0161-7567 (Linking)", "ISSN" : "8750-7587", "PMID" : "17569770", "abstract" : "Low-intensity resistance exercise training combined with blood flow restriction (REFR) increases muscle size and strength as much as conventional resistance exercise with high loads. However, the cellular mechanism(s) underlying the hypertrophy and strength gains induced by REFR are unknown. We have recently shown that both the mammalian target of rapamycin (mTOR) signaling pathway and muscle protein synthesis (MPS) were stimulated after an acute bout of high-intensity resistance exercise in humans. Therefore, we hypothesized that an acute bout of REFR would enhance mTOR signaling and stimulate MPS. We measured MPS and phosphorylation status of mTOR-associated signaling proteins in six young male subjects. Subjects were studied once during blood flow restriction (REFR, bilateral leg extension exercise at 20% of 1 repetition maximum while a pressure cuff was placed on the proximal end of both thighs and inflated at 200 mmHg) and a second time using the same exercise protocol but without the pressure cuff [control (Ctrl)]. MPS in the vastus lateralis muscle was measured by using stable isotope techniques, and the phosphorylation status of signaling proteins was determined by immunoblotting. Blood lactate, cortisol, and growth hormone were higher following REFR compared with Ctrl (P < 0.05). Ribosomal S6 kinase 1 (S6K1) phosphorylation, a downstream target of mTOR, increased concurrently with a decreased eukaryotic translation elongation factor 2 (eEF2) phosphorylation and a 46% increase in MPS following REFR (P < 0.05). MPS and S6K1 phosphorylation were unchanged in the Ctrl group postexercise. We conclude that the activation of the mTOR signaling pathway appears to be an important cellular mechanism that may help explain the enhanced muscle protein synthesis during REFR.", "author" : [ { "dropping-particle" : "", "family" : "Fujita", "given" : "Satoshi", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Abe", "given" : "Takashi", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Drummond", "given" : "Micah J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cadenas", "given" : "Jerson G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Dreyer", "given" : "Hans C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Sato", "given" : "Yoshiaki", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Volpi", "given" : "Elena", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rasmussen", "given" : "Blake B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of applied physiology (Bethesda, Md. : 1985)", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2007" ] ] }, "page" : "903-910", "title" : "Blood flow restriction during low-intensity resistance exercise increases S6K1 phosphorylation and muscle protein synthesis.", "type" : "article-journal", "volume" : "103" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[65]", "plainTextFormattedCitation" : "[65]", "previouslyFormattedCitation" : "[65]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[65]. This increase in MPS was most likely due to the more rapid MU recruitment and resulting increased muscle fiber recruitment associated with earlier fatigue induced by vascular occlusion despite the use of a lower load. Henneman’s size principal ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "0022-0949 (Print)\\r0022-0949 (Linking)", "ISSN" : "0022-0949", "PMID" : "3161974", "abstract" : "Orderly, size-related recruitment of motoneurones (MNs) illustrates how hundreds of cells operate as a functional entity to produce a highly deterministic output. The coherent action of the pool depends largely on the distribution of input to its members through the connections of afferent fibres. Three types of spike-triggered averaging have been utilized to study these connections. Impulses in individual Ia afferents elicit excitatory postsynaptic potentials ('single-fibre' EPSPs) in about 80% of homonymous MNs. After spinal transection 100% may respond, suggesting that Ia fibres project anatomically to all homonymous MNs. Functionally absent Ia connections are due to transmission failure. The sum of all the EPSPs elicited in a large population of MNs was recorded electrotonically from ventral roots. The mean amplitudes of these 'postsynaptic population potentials' (PSPPs) were correlated with the conduction velocities (CVs) of the Ia or spindle group II fibres. The greater the distance between the spinal entry point of a Ia fibre and the ventral root, the smaller was the PSPP. Tape recording of multiple afferents and the responses of up to 24 MNs permitted study of as many as 264 possible connections in a single, acute experiment. Construction of wiring diagrams and connectivity matrices from the data showed that functional connectivity is influenced by afferent fibre size, the effect of branching on fibre size, MN size and probably transmission failure, but that on a cell-to-cell level, connectivity does not follow strict, deterministic rules. The results raise the question of how probabilistic connections between afferent fibres and MNs give rise to deterministic outputs from the whole pool.", "author" : [ { "dropping-particle" : "", "family" : "Henneman", "given" : "E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of experimental biology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1985" ] ] }, "page" : "105-112", "title" : "The size-principle: a deterministic output emerges from a set of probabilistic connections.", "type" : "article-journal", "volume" : "115" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[66]", "plainTextFormattedCitation" : "[66]", "previouslyFormattedCitation" : "[66]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[66] dictates that MUs within a muscle are recruited in an orderly fashion from smallest to largest based on neuronal diameter to generate a required force. MUs that innervate type I fibres tend to have smaller diameters while MU innervating type IIa and IIx muscle fibres have larger neuronal diameters ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Henneman", "given" : "E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Science", "id" : "ITEM-1", "issue" : "3287", "issued" : { "date-parts" : [ [ "1957" ] ] }, "page" : "1345-1347", "title" : "The relation between size of neurons and their susceptibility to discharge", "type" : "article-journal", "volume" : "126" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[67]", "plainTextFormattedCitation" : "[67]", "previouslyFormattedCitation" : "[67]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[67]. For a ‘low demand’ force that is less strenuous, it would be primarily type I MUs would be recruited. In contrast, for a more strenuous demand such as lifting a heavy load, or when vascular occlusion is used to cause premature fatigue, the recruitment of larger MUs innnervating type IIa or type IIx fibres would be more rapid to match the required force output ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Henneman", "given" : "E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Somjen", "given" : "G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Carpenter", "given" : "D O", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Neurophysiology", "id" : "ITEM-1", "issue" : "3", "issued" : { "date-parts" : [ [ "1965" ] ] }, "page" : "560-580", "title" : "Functional Significance of Cell Size in Spinal Motoneurons", "type" : "article-journal", "volume" : "28" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "ISBN" : "0022-3751 (Print) 0022-3751 (Linking)", "ISSN" : "0022-3751", "PMID" : "4350770", "abstract" : "1. The contractile properties of human motor units from the first dorsal interosseus muscle of the hand were studied during voluntary isometric contractions using recently developed techniques.2. The twitch tensions produced by motor units varied widely from about 0.1-10 g. The twitch tension of a motor unit varied nearly linearly as a function of the level of voluntary force at which it was recruited over the entire range of forces studied (0-2 kg).3. The number of additional motor units recruited during a given increment in force declined sharply at high levels of voluntary force. This suggests that even though the high threshold units generate more tension, the contribution of recruitment to increases in voluntary force declines at higher force levels.4. Contraction times for these motor units varied from 30 to 100 msec. Over 80% had contraction times less than 70 msec, and might be classed as fast twitch motor units. The larger motor units, which were recruited at higher threshold forces, tended to have shorter contraction times than the smaller units.", "author" : [ { "dropping-particle" : "", "family" : "Milner-Brown", "given" : "H S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Stein", "given" : "R B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Yemm", "given" : "R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-2", "issued" : { "date-parts" : [ [ "1973" ] ] }, "page" : "359-370", "title" : "The orderly recruitment of human motor units during voluntary isometric contractions.", "type" : "article-journal", "volume" : "230" }, "uris" : [ "" ] }, { "id" : "ITEM-3", "itemData" : { "DOI" : "10.1007/s00421-004-1072-y", "ISBN" : "0042100410", "ISSN" : "14396319", "PMID" : "15205956", "abstract" : "Low-intensity (approximately 50% of a single repetition maximum-1 RM) resistance training combined with vascular occlusion results in increases in muscle strength and cross-sectional area [Takarada et al. (2002) Eur J Appl Physiol 86:308-331]. The mechanisms responsible for this hypertrophy and strength gain remain elusive and no study has assessed the contribution of neuromuscular adaptations to these strength gains. We examined the effect of low-intensity training (8 weeks of unilateral elbow flexion at 50% 1 RM) both with (OCC) and without vascular occlusion (CON) on neuromuscular changes in the elbow flexors of eight previously untrained men [19.5 (0.4) years]. Following training, maximal voluntary dynamic strength increased (P<0.05) in OCC (22%) and CON (23%); however, isometric maximal voluntary contraction (MVC) strength increased in OCC only (8.3%, P<0.05). Motor unit activation, assessed by interpolated twitch, was high (approximately 98%) in OCC and CON both pre- and post-training. Evoked resting twitch torque decreased 21% in OCC (P<0.05) but was not altered in CON. Training resulted in a reduction in the twitch:MVC ratio in OCC only (29%, P<0.01). Post-activation potentiation (PAP) significantly increased by 51% in OCC (P<0.05) and was not changed in CON. We conclude that low-intensity resistance training in combination with vascular occlusion produces an adequate stimulus for increasing muscle strength and causes changes in indices of neuromuscular function, such as depressed resting twitch torque and enhanced PAP.", "author" : [ { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burgomaster", "given" : "Kirsten a.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Schofield", "given" : "Lee M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Gibala", "given" : "Martin J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Sale", "given" : "Digby G.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European Journal of Applied Physiology", "id" : "ITEM-3", "issue" : "4-5", "issued" : { "date-parts" : [ [ "2004" ] ] }, "page" : "399-406", "title" : "Neuromuscular adaptations in human muscle following low intensity resistance training with vascular occlusion", "type" : "article-journal", "volume" : "92" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[68\u201370]", "plainTextFormattedCitation" : "[68\u201370]", "previouslyFormattedCitation" : "[68\u201370]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[68–70]. Taken together, it can be argued that inducing significant fatigue, through BFR, will result in increased MU recruitment and fibre activation resulting in similar hypertrophic adaptations. However, this is not restricted to BFR, since RE with high or low loads, so long as fatigue were achieved, would hypothetically result in hypertrophy of the muscle fibers caused by increased activation ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Thorstensson", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Karlsson", "given" : "J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Viitasalo", "given" : "J H T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Komi", "given" : "P V E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Acta Physiologica Scandinavica", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "1976" ] ] }, "page" : "232-236", "title" : "Effect of Strength Training on EMG of Human Skeletal Muscle", "type" : "article-journal", "volume" : "98" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[24]", "plainTextFormattedCitation" : "[24]", "previouslyFormattedCitation" : "[24]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[24]. Thus, with lower loads it is the repetitive full recruitment of MUs that helps to drive increases in skeletal muscle hypertrophy and strength. Table I lists several studies that have been conducted involving the use of high and low repetition ranges where outcomes measures were hypertrophy and strength. Table I. Overview of studies examining chronic high and low repetition RE protocols on hypertrophy and strength.StudyParticipantsDesignVolume EquatedFailureHypertrophy measureFindingsAlegre et al. (2015)ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1002/mus.24271", "ISSN" : "1097-4598", "PMID" : "24828840", "abstract" : "Introduction: While current exercise guidelines recommend progressive, high-intensity resistance training (RT) to promote muscle hypertrophy and strength gains, controversy exists regarding the efficacy of lighter-load RT. We compared 2 work-matched RT interventions that differed in training intensity. Methods: Fifteen women underwent 10 weeks of unilateral knee extensor RT. One leg was trained at increasing intensity (intensity leg, InL, 50-80% 1-RM), and training progression in the contralateral leg (volume leg, VoL, 50% 1-RM) was based on increasing training volumes. Quadriceps muscle size (ultrasound, DXA) and strength (isokinetic dynamometry) were assessed on 4 occasions. Results: Both training programs induced significant, yet comparable increases in muscle size (InL: +4.6-12%, VoL: +3.1-11%) and strength (InL: +10-16%, VoL: +10-14%). Discussion: Training at lower than commonly suggested intensities may be an equally effective alternative form of RT. Factors other than training intensity, such as the total mechanical work during training, may strongly affect the training response. \u00a9 2014 Wiley Periodicals, Inc.", "author" : [ { "dropping-particle" : "", "family" : "Alegre", "given" : "Luis M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aguado", "given" : "Xavier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rojas-Mart\u00edn", "given" : "Diego", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Mart\u00edn-Garc\u00eda", "given" : "Mar\u00eda", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ara", "given" : "Ignacio", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Csapo", "given" : "Robert", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Muscle & nerve", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2015" ] ] }, "page" : "92-101", "title" : "Load-controlled moderate and high-intensity resistance training programs provoke similar strength gains in young women.", "type" : "article-journal", "volume" : "51" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[71]", "plainTextFormattedCitation" : "[71]", "previouslyFormattedCitation" : "[71]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[71]15 UT young womenUnilateral design with one limb performing increasing intensity (50-80% RM) 3 sets, 6 reps and the other at 50% RM for 3 sets. 3 days per week, 10 weeksYesNoB-mode ultrasound and DXA for muscle massSignificant increases in strength and hypertrophy. No significant difference between groupsBemben et al. (2000)ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1097/00005768-200011000-00020", "ISBN" : "0195-9131 (Print)\\r0195-9131 (Linking)", "ISSN" : "0195-9131", "PMID" : "11079527", "abstract" : "PURPOSE: The purpose of this study was to compare the effects of a high-load (80%, 1-repetition maximum (RM), 8 reps) and a high-repetition (40%, 1-RM, 16 reps) resistance training protocol on muscular strength and bone mineral density (BMD) in early postmenopausal, estrogen-deficient women. The 6-month programs were matched initially for training volume (3 sets, 3 d x wk(-1)) for 12 exercises selected to specifically load the spine and hip. METHODS: Subjects included 25 women (41-60 yr) who were matched by spine BMD then randomly assigned to either the high-load (HL, N = 10), high-repetition (HR, N = 7), or control (C, N = 8) groups. Dietary calcium intakes were supplemented to approximately 1500 mg x d(-1). Total body, spine, and hip BMD (DXA, Lunar Model DPX-IQ), upper and lower body muscular strength, and biochemical markers of bone turnover were measured at baseline and after 6 months of training. RESULTS: There were no group differences in the baseline measures. Both training groups showed similar increases in biceps (20%) and rectus femoris (28-33%) cross-sectional areas, in lower body strength (approximately 30%) and in hip strength (37-40%). HL showed greater improvements in upper body strength (HL 25%, HR 16%). Neither training group experienced significant increases in spine or hip BMD, although the HL total body BMD tended to decrease (-1.1%+/-0.4, P = 0.054) after training. Osteocalcin tended to increase (P = 0.08) in all groups after training, and the % change in osteocalcin was positively related to % changes in the total hip (r = 0.41, P = 0.048) and the trochanter (r = 0.42, P = 0.04) BMD. CONCLUSION: The high-load and high-repetition resistance training protocols were both effective in improving muscular strength and size in postmenopausal women, indicating low-intensity resistance training can be beneficial for the muscular fitness in women for whom high-intensity exercise is contraindicated.", "author" : [ { "dropping-particle" : "", "family" : "Bemben", "given" : "D a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fetters", "given" : "N L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Bemben", "given" : "M G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Nabavi", "given" : "N", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Koh", "given" : "E T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and science in sports and exercise", "id" : "ITEM-1", "issue" : "27", "issued" : { "date-parts" : [ [ "2000" ] ] }, "page" : "1949-1957", "title" : "Musculoskeletal responses to high- and low-intensity resistance training in early postmenopausal women.", "type" : "article-journal", "volume" : "32" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[72]", "plainTextFormattedCitation" : "[72]", "previouslyFormattedCitation" : "[72]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[72]25 UT postmenopausal womenRA to 3 sets of 80%RM for 8 reps or 40% RM for 16 reps. 3 days per week, 6 monthsYesNoB-mode ultrasound, DXASignificant increases in strength and hypertrophy. No significant difference between groups except in upper body strength in which low rep was significantly greaterCampos et al. (2002)ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5]", "plainTextFormattedCitation" : "[5]", "previouslyFormattedCitation" : "[5]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5]32 UT young menRA to either 3-5 RM, 9-11 RM, 20-28 RM. 2-4 sets, 3 days a week, 8 weeksYesNoMuscle biopsy (fibre CSA)Significant increases in CSA for low rep group. Significantly greater increases in strength for low repetitionHolm et al. (2008)ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.90538.2008", "ISBN" : "8750-7587 (Print)", "ISSN" : "8750-7587", "PMID" : "18787090", "abstract" : "Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60 degrees /s. Quadriceps muscle cross-sectional area increased (P < 0.05) 8 +/- 1% and 3 +/- 1% in HL and LL legs, respectively, with a greater gain in HL than LL (P < 0.05). Likewise, 1RM strength increased (P < 0.001) in both legs (HL: 36 +/- 5%, LL: 19 +/- 2%), albeit more so with HL (P < 0.01). Isokinetic 60 degrees /s muscle strength improved by 13 +/- 5% (P < 0.05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.", "author" : [ { "dropping-particle" : "", "family" : "Holm", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Reitelseder", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pedersen", "given" : "T G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Doessing", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Petersen", "given" : "S G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Flyvbjerg", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Andersen", "given" : "J L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aagaard", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kjaer", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Applied Physiology", "id" : "ITEM-1", "issue" : "5", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "1454-1461", "title" : "Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity.", "type" : "article-journal", "volume" : "105" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[64]", "plainTextFormattedCitation" : "[64]", "previouslyFormattedCitation" : "[64]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[64]12 UT young menUnilateral exercise with one limb performing 70% RM for 8 reps and the other limb performing 15.5% RM for 36 reps. 3 days per week, 12 weeksYesNoMRI, muscle biopsySignificant increases in CSA and strength in both groups. Greater increases in low repetitionLéger et al. (2004)ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2006.116715", "ISSN" : "0022-3751", "PMID" : "16916907", "abstract" : "Skeletal muscle size is tightly regulated by the synergy between anabolic and catabolic signalling pathways which, in humans, have not been well characterized. Akt has been suggested to play a pivotal role in the regulation of skeletal muscle hypertrophy and atrophy in rodents and cells. Here we measured the amount of phospho-Akt and several of its downstream anabolic targets (glycogen synthase kinase-3beta (GSK-3beta), mTOR, p70(s6k) and 4E-BP1) and catabolic targets (Foxo1, Foxo3, atrogin-1 and MuRF1). All measurements were performed in human quadriceps muscle biopsies taken after 8 weeks of both hypertrophy-stimulating resistance training and atrophy-stimulating de-training. Following resistance training a muscle hypertrophy ( approximately 10%) and an increase in phospho-Akt, phospho-GSK-3beta and phospho-mTOR protein content were observed. This was paralleled by a decrease in Foxo1 nuclear protein content. Following the de-training period a muscle atrophy (5%), relative to the post-training muscle size, a decrease in phospho-Akt and GSK-3beta and an increase in Foxo1 were observed. Atrogin-1 and MuRF1 increased after the hypertrophy and decreased after the atrophy phases. We demonstrate, for the first time in human skeletal muscle, that the regulation of Akt and its downstream signalling pathways GSK-3beta, mTOR and Foxo1 are associated with both the skeletal muscle hypertrophy and atrophy processes.", "author" : [ { "dropping-particle" : "", "family" : "L\u00e9ger", "given" : "Bertrand", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cartoni", "given" : "Romain", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Praz", "given" : "Manu", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lamon", "given" : "S\u00e9verine", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "D\u00e9riaz", "given" : "Olivier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Crettenand", "given" : "Antoinette", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Gobelet", "given" : "Charles", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rohmer", "given" : "Paul", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Konzelmann", "given" : "Michel", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luthi", "given" : "Fran\u00e7ois", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Russell", "given" : "Aaron P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-1", "issue" : "Pt 3", "issued" : { "date-parts" : [ [ "2006", "11", "1" ] ] }, "page" : "923-33", "title" : "Akt signalling through GSK-3beta, mTOR and Foxo1 is involved in human skeletal muscle hypertrophy and atrophy.", "type" : "article-journal", "volume" : "576" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[61]", "plainTextFormattedCitation" : "[61]", "previouslyFormattedCitation" : "[61]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[61]25 UT young menRA to either 3-5 RM, 9-11 RM, 20-28 RM. 2-4 sets, 3 days a week, 8 weeksYesNoCTSignificant increases in strength and CSA. No significant difference between groupsMitchell et al. (2012)ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6]18 UT young menRA to perform 2 of 3 unilateral leg extension protocols: 3 sets of 30% RM, 3 sets of 80% RM or 1 set of 80% RM. 3 days per week, 10 weeks.NoYesDXA scanNo differences in CSA between low and high repetition. Significantly greater strength gains in low repetitionTaffe et al. (1996)ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1111/j.1475-097X.1996.tb00727.x", "ISBN" : "1365-2281", "ISSN" : "0144-5979", "PMID" : "8842574", "abstract" : "The effects of 52 weeks resistance training at one of two exercise intensities on thigh muscle strength, fiber cross-sectional area (CSA), and tissue composition were studied in healthy 65-79-year-old women. Subjects were assigned to either a control (CO), high-intensity (HI) or low-intensity (LO) training group. Exercise regimens consisted of three sets of leg press, knee extension, and knee flexion exercises, 3 days/week, at either 80% of one-repetition maximum (1-RM) for seven repetitions (HI) or 40% of 1-RM for 14 repetitions (LO). Dynamic muscle strength was evaluated by 1-RM, thigh lean tissue mass (LTM), fat mass, and bone mineral density (BMD, g/cm2) by dual energy X-ray absorptiometry, and fiber CSA of vastus lateralis m. by histomorphometry. Muscle strength increased, on average (+/- SEM), by 59.4 +/- 7.9% and 41.5 +/- 7.9% for HI and LO, respectively, compared to 1.3 +/- 4.8% in CO (P = 0.0001). Type I fiber CSA increased over time (P < 0.05) in both exercise groups, with a trend for increased type II area (HI, P = 0.06; LO, P = 0.11). There was no significant effect of either exercise program on thigh tissue composition, except for BMD at the 1/3 site (middle third of the femur), where LO and CO groups experienced a decline (P < 0.05) of -2.2 +/- 0.5% and -1.8 +/- 0.6%, respectively, while HI maintained BMD (+1.0 +/- 1.0%). Both training programs produced significant gains in thigh muscle strength, which were associated with fiber hypertrophy, although these did not translate into appreciable alterations in thigh tissue composition.", "author" : [ { "dropping-particle" : "", "family" : "Taffe", "given" : "D R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pruitt", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pyka", "given" : "G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Guido", "given" : "D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Marcus", "given" : "R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Clinical physiology (Oxford, England)", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1996" ] ] }, "page" : "381-392", "title" : "Comparative effects of high- and low-intensity resistance training on thigh muscle strength, fiber area, and tissue composition in elderly women.", "type" : "article-journal", "volume" : "16" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[73]", "plainTextFormattedCitation" : "[73]", "previouslyFormattedCitation" : "[73]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[73]36 UT postmenopausal womenRA 3 sets of either 40% RM for 14 reps or 80% RM for 7 reps. 3 days per week 12 weeksYesNoMuscle biopsySignificant increases in strength and CSA. No significant difference between groups36 UT postmenopausal womenRA 3 sets of either 40% RM for 14 reps or 80% RM for 7 reps. 3 days per week 12 weeksYesNoMuscle biopsySignificant increases in strength and CSA. No significant difference between groupsVan Roie et al. (2013)ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1016/j.exger.2013.08.010", "ISSN" : "1873-6815", "PMID" : "23999311", "abstract" : "Muscle adaptations can be induced by high-resistance exercise. Despite being potentially more suitable for older adults, low-resistance exercise protocols have been less investigated. We compared the effects of high- and low-resistance training on muscle volume, muscle strength, and force-velocity characteristics. Fifty-six older adults were randomly assigned to 12 weeks of leg press and leg extension training at either HIGH (2\u00d710-15 repetitions at 80% of one repetition maximum (1RM)), LOW (1\u00d780-100 repetitions at 20% of 1RM), or LOW+ (1\u00d760 repetitions at 20% of 1RM, followed by 1\u00d710-20 repetitions at 40% of 1RM). All protocols ended with muscle failure. Leg press and leg extension of 1RM were measured at baseline and post intervention and before the first training session in weeks 5 and 9. At baseline and post intervention, muscle volume (MV) was measured by CT-scan. A Biodex dynamometer evaluated knee extensor static peak torque in different knee angles (PT(stat90\u00b0), PT(stat120\u00b0), PT(stat150\u00b0)), dynamic peak torque at different speeds (PT(dyn60\u00b0s)(-1), PT(dyn180\u00b0s)(-1), PT(dyn240\u00b0s)(-1)), and speed of movement at 20% (S20), 40% (S40), and 60% (S60) of PTstat90\u00b0. HIGH and LOW+ resulted in greater improvements in 1RM strength than LOW (p<0.05). These differences were already apparent after week 5. Similar gains were found between groups in MV, PT(stat), PT(dyn60\u00b0s)(-1), and PT(dyn180\u00b0s)(-1). No changes were reported in speed of movement. HIGH tended to improve PT(dyn240\u00b0s)(-1) more than LOW or LOW+ (p=0.064). In conclusion, high- and low-resistance exercises ending with muscle failure may be similarly effective for hypertrophy. High-resistance training led to a higher increase in 1RM strength than low-resistance training (20% of 1RM), but this difference disappeared when using a mixed low-resistance protocol in which the resistance was intensified within a single exercise set (40% of 1RM). Our findings support the need for more research on low-resistance programs in older age, in particular long-term training studies and studies focusing on residual effects after training cessation.", "author" : [ { "dropping-particle" : "", "family" : "Roie", "given" : "Evelien", "non-dropping-particle" : "Van", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Delecluse", "given" : "Christophe", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Coudyzer", "given" : "Walter", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Boonen", "given" : "Steven", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Bautmans", "given" : "Ivan", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Experimental gerontology", "id" : "ITEM-1", "issue" : "11", "issued" : { "date-parts" : [ [ "2013", "11" ] ] }, "page" : "1351-61", "publisher" : "Elsevier Inc.", "title" : "Strength training at high versus low external resistance in older adults: effects on muscle volume, muscle strength, and force-velocity characteristics.", "type" : "article-journal", "volume" : "48" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[74]", "plainTextFormattedCitation" : "[74]", "previouslyFormattedCitation" : "[74]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[74]56 UT elderly adultsRA to either 2 sets of 10-15 reps at 80% RM, 1 set of 80-100 reps at 20% RM or 1 set of 60 reps at 20% RM followed by 10-20 reps at 40% RM. 3 days per week, 12 weeksNoYesCTNo differences in muscle volume between groups. Greater increases in strength for groups performing 80% RM and the greater volume of exercise (20% + 40% RM)RM, repetition maximum; CSA, cross-sectional area; CT, computerized tomography; MRI, magnetic resonance imaging; UT, untrained; T, trained; RA, randomly assignedDespite controversies in RT program development, a result of RT-induced hypertrophy is an increase in strength. As the studies detailed in Table I show, as well as the results of a recent meta-analysis ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Schoenfeld", "given" : "Brad J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilson", "given" : "Jacob M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lowery", "given" : "Ryan P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Krieger", "given" : "James W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "id" : "ITEM-1", "issue" : "00", "issued" : { "date-parts" : [ [ "2014" ] ] }, "page" : "1-10", "title" : "Muscular adaptations in low- versus high-load resistance training : A meta-analysis", "type" : "article-journal", "volume" : "00" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[63]", "plainTextFormattedCitation" : "[63]", "previouslyFormattedCitation" : "[63]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[63], evidence is emerging that supports a lack of a divergent hypertrophic response after performing higher or lower repetition RT. As was mentioned previously, Campos et al. ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5]", "plainTextFormattedCitation" : "[5]", "previouslyFormattedCitation" : "[5]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5] reported a significant difference in hypertrophy and strength with high and low repetition RT in untrained men; however, this result was not mirrored when the same program was replicated by Léger et al ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2006.116715", "ISSN" : "0022-3751", "PMID" : "16916907", "abstract" : "Skeletal muscle size is tightly regulated by the synergy between anabolic and catabolic signalling pathways which, in humans, have not been well characterized. Akt has been suggested to play a pivotal role in the regulation of skeletal muscle hypertrophy and atrophy in rodents and cells. Here we measured the amount of phospho-Akt and several of its downstream anabolic targets (glycogen synthase kinase-3beta (GSK-3beta), mTOR, p70(s6k) and 4E-BP1) and catabolic targets (Foxo1, Foxo3, atrogin-1 and MuRF1). All measurements were performed in human quadriceps muscle biopsies taken after 8 weeks of both hypertrophy-stimulating resistance training and atrophy-stimulating de-training. Following resistance training a muscle hypertrophy ( approximately 10%) and an increase in phospho-Akt, phospho-GSK-3beta and phospho-mTOR protein content were observed. This was paralleled by a decrease in Foxo1 nuclear protein content. Following the de-training period a muscle atrophy (5%), relative to the post-training muscle size, a decrease in phospho-Akt and GSK-3beta and an increase in Foxo1 were observed. Atrogin-1 and MuRF1 increased after the hypertrophy and decreased after the atrophy phases. We demonstrate, for the first time in human skeletal muscle, that the regulation of Akt and its downstream signalling pathways GSK-3beta, mTOR and Foxo1 are associated with both the skeletal muscle hypertrophy and atrophy processes.", "author" : [ { "dropping-particle" : "", "family" : "L\u00e9ger", "given" : "Bertrand", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cartoni", "given" : "Romain", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Praz", "given" : "Manu", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lamon", "given" : "S\u00e9verine", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "D\u00e9riaz", "given" : "Olivier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Crettenand", "given" : "Antoinette", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Gobelet", "given" : "Charles", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rohmer", "given" : "Paul", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Konzelmann", "given" : "Michel", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luthi", "given" : "Fran\u00e7ois", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Russell", "given" : "Aaron P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-1", "issue" : "Pt 3", "issued" : { "date-parts" : [ [ "2006", "11", "1" ] ] }, "page" : "923-33", "title" : "Akt signalling through GSK-3beta, mTOR and Foxo1 is involved in human skeletal muscle hypertrophy and atrophy.", "type" : "article-journal", "volume" : "576" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[61]", "plainTextFormattedCitation" : "[61]", "previouslyFormattedCitation" : "[61]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[61] In addition, previous work from our group demonstrated similar increases in quadriceps volume when participants performed RT either at 30% or 80% of their 1RM, with both conditions taken to failure ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6]. Using MRI to quantify quadriceps volume, it was found that there were no significant differences in the increase in quadriceps hypertrophy between the 80-3 and 30-3 groups as can be seen in Figure iii. These data substantiate the notion that lower loads can induce muscle accretion that is comparable to that induced by higher loads. These results were contrasted by a significantly greater increase in 1RM following training in that both 80-3 group demonstrating that heavy loads were superior in inducing strength gains if not muscular hypertrophy ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6]. These significant differences in strength are in contrast to studies in which whole body, high and low load RE programs were compared and found no significant differences between groups in strength or in changes in lean mass as determined by DXA scan following training ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1097/00005768-200011000-00020", "ISBN" : "0195-9131 (Print)\\r0195-9131 (Linking)", "ISSN" : "0195-9131", "PMID" : "11079527", "abstract" : "PURPOSE: The purpose of this study was to compare the effects of a high-load (80%, 1-repetition maximum (RM), 8 reps) and a high-repetition (40%, 1-RM, 16 reps) resistance training protocol on muscular strength and bone mineral density (BMD) in early postmenopausal, estrogen-deficient women. The 6-month programs were matched initially for training volume (3 sets, 3 d x wk(-1)) for 12 exercises selected to specifically load the spine and hip. METHODS: Subjects included 25 women (41-60 yr) who were matched by spine BMD then randomly assigned to either the high-load (HL, N = 10), high-repetition (HR, N = 7), or control (C, N = 8) groups. Dietary calcium intakes were supplemented to approximately 1500 mg x d(-1). Total body, spine, and hip BMD (DXA, Lunar Model DPX-IQ), upper and lower body muscular strength, and biochemical markers of bone turnover were measured at baseline and after 6 months of training. RESULTS: There were no group differences in the baseline measures. Both training groups showed similar increases in biceps (20%) and rectus femoris (28-33%) cross-sectional areas, in lower body strength (approximately 30%) and in hip strength (37-40%). HL showed greater improvements in upper body strength (HL 25%, HR 16%). Neither training group experienced significant increases in spine or hip BMD, although the HL total body BMD tended to decrease (-1.1%+/-0.4, P = 0.054) after training. Osteocalcin tended to increase (P = 0.08) in all groups after training, and the % change in osteocalcin was positively related to % changes in the total hip (r = 0.41, P = 0.048) and the trochanter (r = 0.42, P = 0.04) BMD. CONCLUSION: The high-load and high-repetition resistance training protocols were both effective in improving muscular strength and size in postmenopausal women, indicating low-intensity resistance training can be beneficial for the muscular fitness in women for whom high-intensity exercise is contraindicated.", "author" : [ { "dropping-particle" : "", "family" : "Bemben", "given" : "D a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fetters", "given" : "N L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Bemben", "given" : "M G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Nabavi", "given" : "N", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Koh", "given" : "E T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and science in sports and exercise", "id" : "ITEM-1", "issue" : "27", "issued" : { "date-parts" : [ [ "2000" ] ] }, "page" : "1949-1957", "title" : "Musculoskeletal responses to high- and low-intensity resistance training in early postmenopausal women.", "type" : "article-journal", "volume" : "32" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1111/j.1475-097X.1996.tb00727.x", "ISBN" : "1365-2281", "ISSN" : "0144-5979", "PMID" : "8842574", "abstract" : "The effects of 52 weeks resistance training at one of two exercise intensities on thigh muscle strength, fiber cross-sectional area (CSA), and tissue composition were studied in healthy 65-79-year-old women. Subjects were assigned to either a control (CO), high-intensity (HI) or low-intensity (LO) training group. Exercise regimens consisted of three sets of leg press, knee extension, and knee flexion exercises, 3 days/week, at either 80% of one-repetition maximum (1-RM) for seven repetitions (HI) or 40% of 1-RM for 14 repetitions (LO). Dynamic muscle strength was evaluated by 1-RM, thigh lean tissue mass (LTM), fat mass, and bone mineral density (BMD, g/cm2) by dual energy X-ray absorptiometry, and fiber CSA of vastus lateralis m. by histomorphometry. Muscle strength increased, on average (+/- SEM), by 59.4 +/- 7.9% and 41.5 +/- 7.9% for HI and LO, respectively, compared to 1.3 +/- 4.8% in CO (P = 0.0001). Type I fiber CSA increased over time (P < 0.05) in both exercise groups, with a trend for increased type II area (HI, P = 0.06; LO, P = 0.11). There was no significant effect of either exercise program on thigh tissue composition, except for BMD at the 1/3 site (middle third of the femur), where LO and CO groups experienced a decline (P < 0.05) of -2.2 +/- 0.5% and -1.8 +/- 0.6%, respectively, while HI maintained BMD (+1.0 +/- 1.0%). Both training programs produced significant gains in thigh muscle strength, which were associated with fiber hypertrophy, although these did not translate into appreciable alterations in thigh tissue composition.", "author" : [ { "dropping-particle" : "", "family" : "Taffe", "given" : "D R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pruitt", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pyka", "given" : "G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Guido", "given" : "D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Marcus", "given" : "R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Clinical physiology (Oxford, England)", "id" : "ITEM-2", "issued" : { "date-parts" : [ [ "1996" ] ] }, "page" : "381-392", "title" : "Comparative effects of high- and low-intensity resistance training on thigh muscle strength, fiber area, and tissue composition in elderly women.", "type" : "article-journal", "volume" : "16" }, "uris" : [ "" ] }, { "id" : "ITEM-3", "itemData" : { "DOI" : "10.1002/mus.24271", "ISSN" : "1097-4598", "PMID" : "24828840", "abstract" : "Introduction: While current exercise guidelines recommend progressive, high-intensity resistance training (RT) to promote muscle hypertrophy and strength gains, controversy exists regarding the efficacy of lighter-load RT. We compared 2 work-matched RT interventions that differed in training intensity. Methods: Fifteen women underwent 10 weeks of unilateral knee extensor RT. One leg was trained at increasing intensity (intensity leg, InL, 50-80% 1-RM), and training progression in the contralateral leg (volume leg, VoL, 50% 1-RM) was based on increasing training volumes. Quadriceps muscle size (ultrasound, DXA) and strength (isokinetic dynamometry) were assessed on 4 occasions. Results: Both training programs induced significant, yet comparable increases in muscle size (InL: +4.6-12%, VoL: +3.1-11%) and strength (InL: +10-16%, VoL: +10-14%). Discussion: Training at lower than commonly suggested intensities may be an equally effective alternative form of RT. Factors other than training intensity, such as the total mechanical work during training, may strongly affect the training response. \u00a9 2014 Wiley Periodicals, Inc.", "author" : [ { "dropping-particle" : "", "family" : "Alegre", "given" : "Luis M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aguado", "given" : "Xavier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rojas-Mart\u00edn", "given" : "Diego", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Mart\u00edn-Garc\u00eda", "given" : "Mar\u00eda", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ara", "given" : "Ignacio", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Csapo", "given" : "Robert", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Muscle & nerve", "id" : "ITEM-3", "issue" : "1", "issued" : { "date-parts" : [ [ "2015" ] ] }, "page" : "92-101", "title" : "Load-controlled moderate and high-intensity resistance training programs provoke similar strength gains in young women.", "type" : "article-journal", "volume" : "51" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[71\u201373]", "plainTextFormattedCitation" : "[71\u201373]", "previouslyFormattedCitation" : "[71\u201373]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[71–73]. Clearly the optimal program for augmenting muscle strength and hypertrophy has yet to be elucidated for a healthy population, let alone for specific sub sets. 02162175Figure iii. Percentage change in quadiceps muscle volume following 10 weeks of RE at high load (80% 1RM) and low load (30% 1RM). There was a significant main effect for time (increase in quadicrps volume pre- to post- training, p < 0.0001). N=12 per condition. Drawn using data from Mitchell et al., 2012 ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6].0Figure iii. Percentage change in quadiceps muscle volume following 10 weeks of RE at high load (80% 1RM) and low load (30% 1RM). There was a significant main effect for time (increase in quadicrps volume pre- to post- training, p < 0.0001). N=12 per condition. Drawn using data from Mitchell et al., 2012 ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6].1495425-5651500It should be noted that a common criticism of many of the studies included in Table I is that the participants involved were not experienced resistance trained persons and thus the responses are simply a response to any form of RT to induce hypertrophy in RT-na?ve subjects. Thus, the applicability of these RT protocols may be redundant to a trained population. Indeed, support for the contention that training status matters can be seen in a study by Ahtiainen and colleagues ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-003-0833-3", "ISSN" : "1439-6319", "PMID" : "12734759", "abstract" : "Hormonal and neuromuscular adaptations to strength training were studied in eight male strength athletes (SA) and eight non-strength athletes (NA). The experimental design comprised a 21-week strength-training period. Basal hormonal concentrations of serum total testosterone (T), free testosterone (FT) and cortisol (C) and maximal isometric strength, right leg 1 repetition maximum (RM) of the leg extensors were measured at weeks 0, 7, 14 and 21. Muscle cross-sectional area (CSA) of the quadriceps femoris was measured by magnetic resonance imaging (MRI) at weeks 0 and 21. In addition, the acute heavy resistance exercises (AHRE) (bilateral leg extension, five sets of ten RM, with a 2-min rest between sets) including blood samples for the determination of serum T, FT, C, and GH concentrations were assessed before and after the 21-week training. Significant increases of 20.9% in maximal force and of 5.6% in muscle CSA in NA during the 21-week strength training period were greater than those of 3.9% and -1.8% in SA, respectively. There were no significant changes in serum basal hormone concentrations during the 21-week experiment. AHRE led to significant acute decreases in isometric force and acute increases in serum hormones both at weeks 0 and 21. Basal T concentrations (mean of 0, 7, 14 and 21 weeks) and changes in isometric force after the 21-week period correlated with each other (r=0.84, P<0.01) in SA. The individual changes in the acute T responses between weeks 0 and 21 and the changes in muscle CSA during the 21-week training correlated with each other (r=0.76, P<0.05) in NA. The correlations between T and the changes in isometric strength and in muscle CSA suggest that both serum basal testosterone concentrations and training-induced changes in acute testosterone responses may be important factors for strength development and muscle hypertrophy.", "author" : [ { "dropping-particle" : "", "family" : "Ahtiainen", "given" : "Juha P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pakarinen", "given" : "Arto", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Alen", "given" : "Markku", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "H\u00e4kkinen", "given" : "Keijo", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "6", "issued" : { "date-parts" : [ [ "2003", "8" ] ] }, "page" : "555-63", "title" : "Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men.", "type" : "article-journal", "volume" : "89" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[75]", "plainTextFormattedCitation" : "[75]", "previouslyFormattedCitation" : "[75]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[75] who compared a traditional RT protocol of 6-12 reps per set in untrained participants and strength athletes. They identified a significant increase in CSA of the quadriceps in the untrained participants of approximately 5 cm2 but no significant change in the quadriceps of the experienced weight lifters. The authors attributed a lack of increase in CSA in the trained population to the lack of specificity and potency of the RE stimulus to initiate a hypertrophic response ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-003-0833-3", "ISSN" : "1439-6319", "PMID" : "12734759", "abstract" : "Hormonal and neuromuscular adaptations to strength training were studied in eight male strength athletes (SA) and eight non-strength athletes (NA). The experimental design comprised a 21-week strength-training period. Basal hormonal concentrations of serum total testosterone (T), free testosterone (FT) and cortisol (C) and maximal isometric strength, right leg 1 repetition maximum (RM) of the leg extensors were measured at weeks 0, 7, 14 and 21. Muscle cross-sectional area (CSA) of the quadriceps femoris was measured by magnetic resonance imaging (MRI) at weeks 0 and 21. In addition, the acute heavy resistance exercises (AHRE) (bilateral leg extension, five sets of ten RM, with a 2-min rest between sets) including blood samples for the determination of serum T, FT, C, and GH concentrations were assessed before and after the 21-week training. Significant increases of 20.9% in maximal force and of 5.6% in muscle CSA in NA during the 21-week strength training period were greater than those of 3.9% and -1.8% in SA, respectively. There were no significant changes in serum basal hormone concentrations during the 21-week experiment. AHRE led to significant acute decreases in isometric force and acute increases in serum hormones both at weeks 0 and 21. Basal T concentrations (mean of 0, 7, 14 and 21 weeks) and changes in isometric force after the 21-week period correlated with each other (r=0.84, P<0.01) in SA. The individual changes in the acute T responses between weeks 0 and 21 and the changes in muscle CSA during the 21-week training correlated with each other (r=0.76, P<0.05) in NA. The correlations between T and the changes in isometric strength and in muscle CSA suggest that both serum basal testosterone concentrations and training-induced changes in acute testosterone responses may be important factors for strength development and muscle hypertrophy.", "author" : [ { "dropping-particle" : "", "family" : "Ahtiainen", "given" : "Juha P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pakarinen", "given" : "Arto", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Alen", "given" : "Markku", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "H\u00e4kkinen", "given" : "Keijo", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "6", "issued" : { "date-parts" : [ [ "2003", "8" ] ] }, "page" : "555-63", "title" : "Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men.", "type" : "article-journal", "volume" : "89" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[75]", "plainTextFormattedCitation" : "[75]", "previouslyFormattedCitation" : "[75]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[75]. However, it is more than likely that the trained participants had simply reached a ceiling in their hypertrophic response. It is important to note that the training program in this study ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-003-0833-3", "ISSN" : "1439-6319", "PMID" : "12734759", "abstract" : "Hormonal and neuromuscular adaptations to strength training were studied in eight male strength athletes (SA) and eight non-strength athletes (NA). The experimental design comprised a 21-week strength-training period. Basal hormonal concentrations of serum total testosterone (T), free testosterone (FT) and cortisol (C) and maximal isometric strength, right leg 1 repetition maximum (RM) of the leg extensors were measured at weeks 0, 7, 14 and 21. Muscle cross-sectional area (CSA) of the quadriceps femoris was measured by magnetic resonance imaging (MRI) at weeks 0 and 21. In addition, the acute heavy resistance exercises (AHRE) (bilateral leg extension, five sets of ten RM, with a 2-min rest between sets) including blood samples for the determination of serum T, FT, C, and GH concentrations were assessed before and after the 21-week training. Significant increases of 20.9% in maximal force and of 5.6% in muscle CSA in NA during the 21-week strength training period were greater than those of 3.9% and -1.8% in SA, respectively. There were no significant changes in serum basal hormone concentrations during the 21-week experiment. AHRE led to significant acute decreases in isometric force and acute increases in serum hormones both at weeks 0 and 21. Basal T concentrations (mean of 0, 7, 14 and 21 weeks) and changes in isometric force after the 21-week period correlated with each other (r=0.84, P<0.01) in SA. The individual changes in the acute T responses between weeks 0 and 21 and the changes in muscle CSA during the 21-week training correlated with each other (r=0.76, P<0.05) in NA. The correlations between T and the changes in isometric strength and in muscle CSA suggest that both serum basal testosterone concentrations and training-induced changes in acute testosterone responses may be important factors for strength development and muscle hypertrophy.", "author" : [ { "dropping-particle" : "", "family" : "Ahtiainen", "given" : "Juha P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pakarinen", "given" : "Arto", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Alen", "given" : "Markku", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "H\u00e4kkinen", "given" : "Keijo", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "6", "issued" : { "date-parts" : [ [ "2003", "8" ] ] }, "page" : "555-63", "title" : "Muscle hypertrophy, hormonal adaptations and strength development during strength training in strength-trained and untrained men.", "type" : "article-journal", "volume" : "89" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[75]", "plainTextFormattedCitation" : "[75]", "previouslyFormattedCitation" : "[75]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[75] was not supervised and thus it is possible that participants did not fully adhere to the experimental instruction prescribed. The marginal hypertrophic response in a previously resistance trained population is not unanticipated since studies in which the acute MPS response to RE in the trained and untrained condition have shown a dampened MPS response in the trained state. For example, Tang et al., investigated the acute MPS response to a high intensity bout of RE following an 8-week intervention where only one limb of each subject performed RE ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/ajpregu.00636.2007", "ISBN" : "0363-6119 (Print)\\r0363-6119 (Linking)", "ISSN" : "0363-6119", "PMID" : "18032468", "abstract" : "Ten healthy young men (21.0 +/- 1.5 yr, 1.79 +/- 0.1 m, 82.7 +/- 14.7 kg, means +/- SD) participated in 8 wk of intense unilateral resistance training (knee extension exercise) such that one leg was trained (T) and the other acted as an untrained (UT) control. After the 8 wk of unilateral training, infusions of L-[ring-d(5)]phenylalanine, L-[ring-(13)C(6)]phenylalanine, and d(3)-alpha-ketoisocaproic acid were used to measure mixed muscle protein synthesis in the T and UT legs by the direct incorporation method [fractional synthetic rate (FSR)]. Protein synthesis was determined at rest as well as 4 h and 28 h after an acute bout of resistance exercise performed at the same intensity relative to the gain in single repetition maximum before and after training. Training increased mean muscle fiber cross-sectional area only in the T leg (type I: 16 +/- 10%; type II: 20 +/- 19%, P < 0.05). Acute resistance exercise increased muscle protein FSR in both legs at 4 h (T: 162 +/- 76%; UT: 108 +/- 62%, P < 0.01 vs. rest) with the increase in the T leg being significantly higher than in the UT leg at this time (P < 0.01). At 28 h postexercise, FSR in the T leg had returned to resting levels; however, the rate of protein synthesis in the UT leg remained elevated above resting (70 +/- 49%, P < 0.01). We conclude that resistance training attenuates the protein synthetic response to acute resistance exercise, despite higher initial increases in FSR, by shortening the duration for which protein synthesis is elevated.", "author" : [ { "dropping-particle" : "", "family" : "Tang", "given" : "Jason E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Perco", "given" : "Jennifer G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilkinson", "given" : "Sarah B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American journal of physiology. Regulatory, integrative and comparative physiology", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "R172-R178", "title" : "Resistance training alters the response of fed state mixed muscle protein synthesis in young men.", "type" : "article-journal", "volume" : "294" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[76]", "plainTextFormattedCitation" : "[76]", "previouslyFormattedCitation" : "[76]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[76]. In this model, MPS was measured in both a trained and untrained state from the same person. They found that RE resulted in a significantly elevated MPS in both the trained and untrained leg 4 hours following exercise however, it was only in the untrained leg that MPS remained significantly elevated following 28 hours ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/ajpregu.00636.2007", "ISBN" : "0363-6119 (Print)\\r0363-6119 (Linking)", "ISSN" : "0363-6119", "PMID" : "18032468", "abstract" : "Ten healthy young men (21.0 +/- 1.5 yr, 1.79 +/- 0.1 m, 82.7 +/- 14.7 kg, means +/- SD) participated in 8 wk of intense unilateral resistance training (knee extension exercise) such that one leg was trained (T) and the other acted as an untrained (UT) control. After the 8 wk of unilateral training, infusions of L-[ring-d(5)]phenylalanine, L-[ring-(13)C(6)]phenylalanine, and d(3)-alpha-ketoisocaproic acid were used to measure mixed muscle protein synthesis in the T and UT legs by the direct incorporation method [fractional synthetic rate (FSR)]. Protein synthesis was determined at rest as well as 4 h and 28 h after an acute bout of resistance exercise performed at the same intensity relative to the gain in single repetition maximum before and after training. Training increased mean muscle fiber cross-sectional area only in the T leg (type I: 16 +/- 10%; type II: 20 +/- 19%, P < 0.05). Acute resistance exercise increased muscle protein FSR in both legs at 4 h (T: 162 +/- 76%; UT: 108 +/- 62%, P < 0.01 vs. rest) with the increase in the T leg being significantly higher than in the UT leg at this time (P < 0.01). At 28 h postexercise, FSR in the T leg had returned to resting levels; however, the rate of protein synthesis in the UT leg remained elevated above resting (70 +/- 49%, P < 0.01). We conclude that resistance training attenuates the protein synthetic response to acute resistance exercise, despite higher initial increases in FSR, by shortening the duration for which protein synthesis is elevated.", "author" : [ { "dropping-particle" : "", "family" : "Tang", "given" : "Jason E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Perco", "given" : "Jennifer G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilkinson", "given" : "Sarah B", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American journal of physiology. Regulatory, integrative and comparative physiology", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "R172-R178", "title" : "Resistance training alters the response of fed state mixed muscle protein synthesis in young men.", "type" : "article-journal", "volume" : "294" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[76]", "plainTextFormattedCitation" : "[76]", "previouslyFormattedCitation" : "[76]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[76]. This is in slight contrast to the results of Kim and colleagues ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2005.093708", "ISSN" : "0022-3751", "PMID" : "16051622", "abstract" : "The purpose of the present investigation was to determine how fasted-state protein synthesis was affected, acutely, by resistance training. Eight men (24.8+/-1.7 years, body mass index=23.2+/-1.0 kg m-2; means+/-s.e.m.) undertook an 8 week programme of unilateral resistance exercise training (3 sessions week-1, progression from two to four sets; intensity was 80% of the subjects' single repetition maximum (1RM): knee extension and leg press). Following training, subjects underwent two primed constant infusions of l-[ring-13C6]phenylalanine to determine mixed and myofibrillar muscle protein synthesis (MPS) at rest and 12 h after an acute bout of resistance exercise at the same exercise intensity--each leg 80% of 1RM. Biopsies (vastus lateralis) were taken to measure incorporation of labelled phenylalanine into mixed and myofibrillar skeletal muscle proteins and yield fractional MPS. Training resulted in significant dynamic strength gains that were greater (P<0.001) in the trained leg. Hypertrophy of type IIa and IIx fibres (P<0.05) was observed following training. After training, resting mixed MPS rate was elevated (+48%; P<0.05). Acutely, resistance exercise stimulated mixed MPS only in the untrained leg (P<0.05). Myofibrillar MPS was unchanged at rest following training (P=0.61). Myofibrillar MPS increased after resistance exercise (P<0.05), but was not different between the trained and untrained legs (P=0.36). We observed divergent changes in resting mixed versus myofibrillar protein synthesis with training. In addition, resistance training modified the acute response of MPS to resistance exercise by dampening the increased synthesis of non-myofibrillar proteins while maintaining the synthesis of myofibrillar proteins.", "author" : [ { "dropping-particle" : "", "family" : "Kim", "given" : "Paul L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-1", "issue" : "Pt 1", "issued" : { "date-parts" : [ [ "2005", "10", "1" ] ] }, "page" : "283-90", "title" : "Fasted-state skeletal muscle protein synthesis after resistance exercise is altered with training.", "type" : "article-journal", "volume" : "568" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[30]", "plainTextFormattedCitation" : "[30]", "previouslyFormattedCitation" : "[30]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[30] who saw no increase in FSR following RT in the trained leg but a significant increase in the untrained leg by 132% from baseline. It should be specified that the measurement of MPS in both the previous examples were of mixed muscle protein synthesis meaning that they incorporate the sarcoplasmic, mitochondrial, and myofibrillar fractions. When Kim and colleagues examined the myofibrillar fraction alone, they demonstrated a very similar, significant increase in both the trained (44%) and untrained (42%) legs as shown in Figure iv below. centertopFigure iv. A - mixed muscle protein FSR (% h-1) in the UT and T legs at rest and following an acute bout of RE. * Significantly different (p < 0.01) from the same value in the UT state; +Significantly different from rest in the same leg (p < 0.05). B - myofibrillar protein FSR (% h-1) in the UT and T legs at rest and following an acute bout of RE. +Significantly different from rest (main effect for exercise; p < 0.05). Note differences in axes scales between panels A and B. Values are means ± S.E.M. (n = 8). Data taken with permission from Kim et al, 2005 ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2005.093708", "ISSN" : "0022-3751", "PMID" : "16051622", "abstract" : "The purpose of the present investigation was to determine how fasted-state protein synthesis was affected, acutely, by resistance training. Eight men (24.8+/-1.7 years, body mass index=23.2+/-1.0 kg m-2; means+/-s.e.m.) undertook an 8 week programme of unilateral resistance exercise training (3 sessions week-1, progression from two to four sets; intensity was 80% of the subjects' single repetition maximum (1RM): knee extension and leg press). Following training, subjects underwent two primed constant infusions of l-[ring-13C6]phenylalanine to determine mixed and myofibrillar muscle protein synthesis (MPS) at rest and 12 h after an acute bout of resistance exercise at the same exercise intensity--each leg 80% of 1RM. Biopsies (vastus lateralis) were taken to measure incorporation of labelled phenylalanine into mixed and myofibrillar skeletal muscle proteins and yield fractional MPS. Training resulted in significant dynamic strength gains that were greater (P<0.001) in the trained leg. Hypertrophy of type IIa and IIx fibres (P<0.05) was observed following training. After training, resting mixed MPS rate was elevated (+48%; P<0.05). Acutely, resistance exercise stimulated mixed MPS only in the untrained leg (P<0.05). Myofibrillar MPS was unchanged at rest following training (P=0.61). Myofibrillar MPS increased after resistance exercise (P<0.05), but was not different between the trained and untrained legs (P=0.36). We observed divergent changes in resting mixed versus myofibrillar protein synthesis with training. In addition, resistance training modified the acute response of MPS to resistance exercise by dampening the increased synthesis of non-myofibrillar proteins while maintaining the synthesis of myofibrillar proteins.", "author" : [ { "dropping-particle" : "", "family" : "Kim", "given" : "Paul L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-1", "issue" : "Pt 1", "issued" : { "date-parts" : [ [ "2005", "10", "1" ] ] }, "page" : "283-90", "title" : "Fasted-state skeletal muscle protein synthesis after resistance exercise is altered with training.", "type" : "article-journal", "volume" : "568" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[30]", "plainTextFormattedCitation" : "[30]", "previouslyFormattedCitation" : "[30]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[30].Figure iv. A - mixed muscle protein FSR (% h-1) in the UT and T legs at rest and following an acute bout of RE. * Significantly different (p < 0.01) from the same value in the UT state; +Significantly different from rest in the same leg (p < 0.05). B - myofibrillar protein FSR (% h-1) in the UT and T legs at rest and following an acute bout of RE. +Significantly different from rest (main effect for exercise; p < 0.05). Note differences in axes scales between panels A and B. Values are means ± S.E.M. (n = 8). Data taken with permission from Kim et al, 2005 ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2005.093708", "ISSN" : "0022-3751", "PMID" : "16051622", "abstract" : "The purpose of the present investigation was to determine how fasted-state protein synthesis was affected, acutely, by resistance training. Eight men (24.8+/-1.7 years, body mass index=23.2+/-1.0 kg m-2; means+/-s.e.m.) undertook an 8 week programme of unilateral resistance exercise training (3 sessions week-1, progression from two to four sets; intensity was 80% of the subjects' single repetition maximum (1RM): knee extension and leg press). Following training, subjects underwent two primed constant infusions of l-[ring-13C6]phenylalanine to determine mixed and myofibrillar muscle protein synthesis (MPS) at rest and 12 h after an acute bout of resistance exercise at the same exercise intensity--each leg 80% of 1RM. Biopsies (vastus lateralis) were taken to measure incorporation of labelled phenylalanine into mixed and myofibrillar skeletal muscle proteins and yield fractional MPS. Training resulted in significant dynamic strength gains that were greater (P<0.001) in the trained leg. Hypertrophy of type IIa and IIx fibres (P<0.05) was observed following training. After training, resting mixed MPS rate was elevated (+48%; P<0.05). Acutely, resistance exercise stimulated mixed MPS only in the untrained leg (P<0.05). Myofibrillar MPS was unchanged at rest following training (P=0.61). Myofibrillar MPS increased after resistance exercise (P<0.05), but was not different between the trained and untrained legs (P=0.36). We observed divergent changes in resting mixed versus myofibrillar protein synthesis with training. In addition, resistance training modified the acute response of MPS to resistance exercise by dampening the increased synthesis of non-myofibrillar proteins while maintaining the synthesis of myofibrillar proteins.", "author" : [ { "dropping-particle" : "", "family" : "Kim", "given" : "Paul L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-1", "issue" : "Pt 1", "issued" : { "date-parts" : [ [ "2005", "10", "1" ] ] }, "page" : "283-90", "title" : "Fasted-state skeletal muscle protein synthesis after resistance exercise is altered with training.", "type" : "article-journal", "volume" : "568" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[30]", "plainTextFormattedCitation" : "[30]", "previouslyFormattedCitation" : "[30]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[30].Kim et al. ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2005.093708", "ISSN" : "0022-3751", "PMID" : "16051622", "abstract" : "The purpose of the present investigation was to determine how fasted-state protein synthesis was affected, acutely, by resistance training. Eight men (24.8+/-1.7 years, body mass index=23.2+/-1.0 kg m-2; means+/-s.e.m.) undertook an 8 week programme of unilateral resistance exercise training (3 sessions week-1, progression from two to four sets; intensity was 80% of the subjects' single repetition maximum (1RM): knee extension and leg press). Following training, subjects underwent two primed constant infusions of l-[ring-13C6]phenylalanine to determine mixed and myofibrillar muscle protein synthesis (MPS) at rest and 12 h after an acute bout of resistance exercise at the same exercise intensity--each leg 80% of 1RM. Biopsies (vastus lateralis) were taken to measure incorporation of labelled phenylalanine into mixed and myofibrillar skeletal muscle proteins and yield fractional MPS. Training resulted in significant dynamic strength gains that were greater (P<0.001) in the trained leg. Hypertrophy of type IIa and IIx fibres (P<0.05) was observed following training. After training, resting mixed MPS rate was elevated (+48%; P<0.05). Acutely, resistance exercise stimulated mixed MPS only in the untrained leg (P<0.05). Myofibrillar MPS was unchanged at rest following training (P=0.61). Myofibrillar MPS increased after resistance exercise (P<0.05), but was not different between the trained and untrained legs (P=0.36). We observed divergent changes in resting mixed versus myofibrillar protein synthesis with training. In addition, resistance training modified the acute response of MPS to resistance exercise by dampening the increased synthesis of non-myofibrillar proteins while maintaining the synthesis of myofibrillar proteins.", "author" : [ { "dropping-particle" : "", "family" : "Kim", "given" : "Paul L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-1", "issue" : "Pt 1", "issued" : { "date-parts" : [ [ "2005", "10", "1" ] ] }, "page" : "283-90", "title" : "Fasted-state skeletal muscle protein synthesis after resistance exercise is altered with training.", "type" : "article-journal", "volume" : "568" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[30]", "plainTextFormattedCitation" : "[30]", "previouslyFormattedCitation" : "[30]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[30] speculated that in the untrained state, RE is a novel stimulus and thus creates a disturbance in homeostatic balance causing an increase in the synthesis of all proteins. This is compared to the trained state where RE is no longer a novel stimulus and thus the rise in MPS is less pronounced in response to the exercise. The result is that in a trained state, the stimulus of RE is preferentially directed towards the synthesis of myofibrillar proteins that are essential for hypertrophy ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2005.093708", "ISSN" : "0022-3751", "PMID" : "16051622", "abstract" : "The purpose of the present investigation was to determine how fasted-state protein synthesis was affected, acutely, by resistance training. Eight men (24.8+/-1.7 years, body mass index=23.2+/-1.0 kg m-2; means+/-s.e.m.) undertook an 8 week programme of unilateral resistance exercise training (3 sessions week-1, progression from two to four sets; intensity was 80% of the subjects' single repetition maximum (1RM): knee extension and leg press). Following training, subjects underwent two primed constant infusions of l-[ring-13C6]phenylalanine to determine mixed and myofibrillar muscle protein synthesis (MPS) at rest and 12 h after an acute bout of resistance exercise at the same exercise intensity--each leg 80% of 1RM. Biopsies (vastus lateralis) were taken to measure incorporation of labelled phenylalanine into mixed and myofibrillar skeletal muscle proteins and yield fractional MPS. Training resulted in significant dynamic strength gains that were greater (P<0.001) in the trained leg. Hypertrophy of type IIa and IIx fibres (P<0.05) was observed following training. After training, resting mixed MPS rate was elevated (+48%; P<0.05). Acutely, resistance exercise stimulated mixed MPS only in the untrained leg (P<0.05). Myofibrillar MPS was unchanged at rest following training (P=0.61). Myofibrillar MPS increased after resistance exercise (P<0.05), but was not different between the trained and untrained legs (P=0.36). We observed divergent changes in resting mixed versus myofibrillar protein synthesis with training. In addition, resistance training modified the acute response of MPS to resistance exercise by dampening the increased synthesis of non-myofibrillar proteins while maintaining the synthesis of myofibrillar proteins.", "author" : [ { "dropping-particle" : "", "family" : "Kim", "given" : "Paul L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-1", "issue" : "Pt 1", "issued" : { "date-parts" : [ [ "2005", "10", "1" ] ] }, "page" : "283-90", "title" : "Fasted-state skeletal muscle protein synthesis after resistance exercise is altered with training.", "type" : "article-journal", "volume" : "568" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[30]", "plainTextFormattedCitation" : "[30]", "previouslyFormattedCitation" : "[30]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[30]. Taken together, it appears that the capacity does exist for a resistance-trained population to benefit from additional RE however, how load affects these adaptations remains unknown. VIStatement of Research Question and HypothesisIt is clear from the review of published data that there exists a number of studies that suggest RE load is not a variable that markedly affects RT-induced training hypertrophy so long as loads are lifted to fatigue ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1113/jphysiol.2006.116715", "ISSN" : "0022-3751", "PMID" : "16916907", "abstract" : "Skeletal muscle size is tightly regulated by the synergy between anabolic and catabolic signalling pathways which, in humans, have not been well characterized. Akt has been suggested to play a pivotal role in the regulation of skeletal muscle hypertrophy and atrophy in rodents and cells. Here we measured the amount of phospho-Akt and several of its downstream anabolic targets (glycogen synthase kinase-3beta (GSK-3beta), mTOR, p70(s6k) and 4E-BP1) and catabolic targets (Foxo1, Foxo3, atrogin-1 and MuRF1). All measurements were performed in human quadriceps muscle biopsies taken after 8 weeks of both hypertrophy-stimulating resistance training and atrophy-stimulating de-training. Following resistance training a muscle hypertrophy ( approximately 10%) and an increase in phospho-Akt, phospho-GSK-3beta and phospho-mTOR protein content were observed. This was paralleled by a decrease in Foxo1 nuclear protein content. Following the de-training period a muscle atrophy (5%), relative to the post-training muscle size, a decrease in phospho-Akt and GSK-3beta and an increase in Foxo1 were observed. Atrogin-1 and MuRF1 increased after the hypertrophy and decreased after the atrophy phases. We demonstrate, for the first time in human skeletal muscle, that the regulation of Akt and its downstream signalling pathways GSK-3beta, mTOR and Foxo1 are associated with both the skeletal muscle hypertrophy and atrophy processes.", "author" : [ { "dropping-particle" : "", "family" : "L\u00e9ger", "given" : "Bertrand", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cartoni", "given" : "Romain", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Praz", "given" : "Manu", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lamon", "given" : "S\u00e9verine", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "D\u00e9riaz", "given" : "Olivier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Crettenand", "given" : "Antoinette", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Gobelet", "given" : "Charles", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rohmer", "given" : "Paul", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Konzelmann", "given" : "Michel", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luthi", "given" : "Fran\u00e7ois", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Russell", "given" : "Aaron P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-2", "issue" : "Pt 3", "issued" : { "date-parts" : [ [ "2006", "11", "1" ] ] }, "page" : "923-33", "title" : "Akt signalling through GSK-3beta, mTOR and Foxo1 is involved in human skeletal muscle hypertrophy and atrophy.", "type" : "article-journal", "volume" : "576" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6,61]", "plainTextFormattedCitation" : "[6,61]", "previouslyFormattedCitation" : "[6,61]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6,61]. There are however, several studies that suggest that resistance exercise load is crucial in determining gains in measures of strength ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1152/japplphysiol.90538.2008", "ISBN" : "8750-7587 (Print)", "ISSN" : "8750-7587", "PMID" : "18787090", "abstract" : "Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60 degrees /s. Quadriceps muscle cross-sectional area increased (P < 0.05) 8 +/- 1% and 3 +/- 1% in HL and LL legs, respectively, with a greater gain in HL than LL (P < 0.05). Likewise, 1RM strength increased (P < 0.001) in both legs (HL: 36 +/- 5%, LL: 19 +/- 2%), albeit more so with HL (P < 0.01). Isokinetic 60 degrees /s muscle strength improved by 13 +/- 5% (P < 0.05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.", "author" : [ { "dropping-particle" : "", "family" : "Holm", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Reitelseder", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pedersen", "given" : "T G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Doessing", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Petersen", "given" : "S G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Flyvbjerg", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Andersen", "given" : "J L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aagaard", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kjaer", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Applied Physiology", "id" : "ITEM-2", "issue" : "5", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "1454-1461", "title" : "Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity.", "type" : "article-journal", "volume" : "105" }, "uris" : [ "" ] }, { "id" : "ITEM-3", "itemData" : { "DOI" : "10.1016/j.exger.2013.08.010", "ISSN" : "1873-6815", "PMID" : "23999311", "abstract" : "Muscle adaptations can be induced by high-resistance exercise. Despite being potentially more suitable for older adults, low-resistance exercise protocols have been less investigated. We compared the effects of high- and low-resistance training on muscle volume, muscle strength, and force-velocity characteristics. Fifty-six older adults were randomly assigned to 12 weeks of leg press and leg extension training at either HIGH (2\u00d710-15 repetitions at 80% of one repetition maximum (1RM)), LOW (1\u00d780-100 repetitions at 20% of 1RM), or LOW+ (1\u00d760 repetitions at 20% of 1RM, followed by 1\u00d710-20 repetitions at 40% of 1RM). All protocols ended with muscle failure. Leg press and leg extension of 1RM were measured at baseline and post intervention and before the first training session in weeks 5 and 9. At baseline and post intervention, muscle volume (MV) was measured by CT-scan. A Biodex dynamometer evaluated knee extensor static peak torque in different knee angles (PT(stat90\u00b0), PT(stat120\u00b0), PT(stat150\u00b0)), dynamic peak torque at different speeds (PT(dyn60\u00b0s)(-1), PT(dyn180\u00b0s)(-1), PT(dyn240\u00b0s)(-1)), and speed of movement at 20% (S20), 40% (S40), and 60% (S60) of PTstat90\u00b0. HIGH and LOW+ resulted in greater improvements in 1RM strength than LOW (p<0.05). These differences were already apparent after week 5. Similar gains were found between groups in MV, PT(stat), PT(dyn60\u00b0s)(-1), and PT(dyn180\u00b0s)(-1). No changes were reported in speed of movement. HIGH tended to improve PT(dyn240\u00b0s)(-1) more than LOW or LOW+ (p=0.064). In conclusion, high- and low-resistance exercises ending with muscle failure may be similarly effective for hypertrophy. High-resistance training led to a higher increase in 1RM strength than low-resistance training (20% of 1RM), but this difference disappeared when using a mixed low-resistance protocol in which the resistance was intensified within a single exercise set (40% of 1RM). Our findings support the need for more research on low-resistance programs in older age, in particular long-term training studies and studies focusing on residual effects after training cessation.", "author" : [ { "dropping-particle" : "", "family" : "Roie", "given" : "Evelien", "non-dropping-particle" : "Van", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Delecluse", "given" : "Christophe", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Coudyzer", "given" : "Walter", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Boonen", "given" : "Steven", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Bautmans", "given" : "Ivan", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Experimental gerontology", "id" : "ITEM-3", "issue" : "11", "issued" : { "date-parts" : [ [ "2013", "11" ] ] }, "page" : "1351-61", "publisher" : "Elsevier Inc.", "title" : "Strength training at high versus low external resistance in older adults: effects on muscle volume, muscle strength, and force-velocity characteristics.", "type" : "article-journal", "volume" : "48" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5,64,74]", "plainTextFormattedCitation" : "[5,64,74]", "previouslyFormattedCitation" : "[5,64,74]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5,64,74]. It is my contention that the discrepancies in strength gains may be a result of lack of full fibre recruitment in groups performing sets at a lower load as well as using equated volume between the groups. In an attempt to reconcile existing evidence debating the variation in strength gains with low load RE we aimed to assess the effects of 12 weeks of RT with ~30-50% of 1RM (20-25 repetitions) as compared with ~70-80% of 1RM (8-12 repetitions) both to volitional failure on skeletal muscle hypertrophy and strength. Specifically, it was hypothesized that significant increases in strength and skeletal muscle accrual would be observed with no differences between repetition range groups. These results are expected, since those performing 20-25 repetitions per set will perform a greater volume (repetitions x load) of work compared to those performing 8-12 repetitions per set and also result in greater fatigue at the end of each set (HR, 50-70% fatigued and LR, 20-30% fatigued). I also propose that the use of trained participants for this investigation will help to eliminate strength increases between the groups due to neural factors as these participants should have already attained strength via neural adaptations previously. CHAPTER IIRESISTANCE EXERCISE LOAD DOES NOT MEDIATE SKELETAL MUSCLE HYPERTROPHY AND STRENGTH INCREASES IN TRAINED YOUNG MEN1.Methods1.1 Participants and EthicsForty-nine healthy, active males, (mean ± SD, 23 ± 1 years, 85.9 ± 2.2 kg, 181 ± 1 cm) that were resistance training for at least the past 2 years (4.4 ± 2.3 years, training > 2 sessions per week, for the past 2 years including at least 1 lower body session) volunteered to participate in this study. The rationale for choosing trained participants was to allow for comparison between trained versus untrained persons from a similar study, but in an untrained population ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6]. Participants did not have any existing musculoskeletal conditions and were free of consuming anabolic steroids or other agents known to increase muscle mass. All participants were informed of the purpose of the study, experimental procedures and associated risks prior to participation and exercise testing. All participants gave verbal and written consent to the protocol approved by the Hamilton Integrated Research Ethics Board, conforming to the standards for the use of human subjects in research as outlined in the most recent Tri-Council policy statement on the use of human participants in research (). Participants’ characteristics can be seen in Table 1.VariableHR (n=24)LR (n=25)p Age, y23 ± 223 ± 30.73Total body mass, kg84.6 ± 11.787.1 ± 18.20.57Height, m1.81 ± 1.01.80 ± 1.00.81BMI, kg/m226.9 ± 4.626.0 ± 2.90.41Lean mass, kg65.7 ± 7.665.7 ± 7.40.99Total fat mass, %22.3 ± 7.020.2 ± 5.70.26Leg press 1RM, kg a357 ± 62353 ± 820.87Bench press 1RM, kg a98 ± 1997 ± 170.88Leg extension 1RM, kg a76 ± 1576 ± 150.92Shoulder press 1RM, kg a91 ± 1892 ± 220.87Table 1. Participants' characteristics at baselineValues are means ± SD, HR, high repetition group (20-25 repetitions per set), LR, low repetition group (8-12 repetitions per set). a Maximal isotonic strength measured as single best weight lifted (see METHODS for details). 1.2.Experimental DesignParticipants completed 12-weeks of whole-body resistance exercise training in a between-group design. Subjects were allocated to one of two possible conditions: performing three sets of 20-25 repetitions per set (~35-50% of 1RM), which we refer to as high repetition (HR) or performing three sets of 8-12 repetitions per set at approximately (~70-85% of 1RM), which we refer to as low repetition (LR).1.3Familiarization and Muscle StrengthTwo weeks prior to the start of the training protocol, participants reported to the Exercise and Metabolism Research Laboratory and completed a familiarization session with all related exercise equipment to determine appropriate 10RM loads. Following 48-hours of rest from any exercise, participants returned to the laboratory to complete 1RM testing for the leg press (Maxam Fitness, Hamilton, ON, CAN), bench press, leg extension (Atlantis Inc., Laval, PQ, CAN), and shoulder press (Life Fitness, Rosemont, IL, USA). 1RM tests were completed at the start of each week during training following the completion of every 3-weeks of training and then again following the final training session. All strength testing was performed in strict and rigorous fashion by the same investigator and in accordance with published guidelines for assessment of strength. In brief, participants performed a warm-up prior to testing that consisted of light cardiorespiratory exercise on a cycle ergometer for ~5 minutes. A specific warm up of the given exercise was then performed at approximately 50% of the participant’s estimated 1RM based on 10RM testing ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISSN" : "0022-4707", "author" : [ { "dropping-particle" : "", "family" : "Mayhew", "given" : "J L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Prinster", "given" : "J L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ware", "given" : "J S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Zimmer", "given" : "D L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Arabas", "given" : "J R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Bemben", "given" : "M G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of sports medicine and physical fitness", "id" : "ITEM-1", "issue" : "2", "issued" : { "date-parts" : [ [ "1995" ] ] }, "language" : "eng", "page" : "108-113", "publisher-place" : "Human Performance Laboratory, Northeast Missouri State University, Kirksville 63501, USA.", "title" : "Muscular endurance repetitions to predict bench press strength in men of different training levels", "type" : "article-journal", "volume" : "35" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[77]", "plainTextFormattedCitation" : "[77]", "previouslyFormattedCitation" : "[77]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[77]. Following the warm up, weight was increased by 10-20% for one repetition. Three to five minutes was of rest were given between each attempt. A successful attempt of 1RM was determined by full range of motion which was considered to be complete by the following: leg press 1RM, knee flexion of 90 degrees followed by full extension of the knees; bench press 1RM, contact of the bar against the chest in five-point body contact position followed by full extension of the elbows; for leg extension 1RM, full extension of the knee; for shoulder press 1RM, full extension of the elbows from a starting position of 90 degrees. 1.4Body CompositionBody composition was assessed at the same time of day and in the same condition for each participant throughout the protocol. Following an overnight fast (~12h), when the participants were euhydrated and had not exercised for at least 24-hour prior. Dual-energy X-ray absorptiometry (DXA) measurements were conducted using a GE Lunar iDXA total body scanner (GE Medical Systems Lunar, Madison, WI, USA) and analyzed with software (Lunar enCORE version 14.1, GE Medical Systems Lunar, Madison WI, USA) in the medium scan mode. The machine was calibrated daily by using a 3-compartment Universal Whole Body DXA Phantom (Oscar, Jr; Orthometrix, Naples, FL). Participants were measured while wearing a pair of compression shorts (same for all scans). Each scan lasted ~10 minutes. The analysis regions used were standard regions where the head, torso, arms, and legs were subdivided by the software, but were subsequently checked manually, and in a blinded-manner, by an investigator. 1.5Resistance Training ProtocolThe RE-protocol consisted of 3 sets of 5 exercises per session that targeted all major muscle groups. Training sessions were circuit style and included 2 supersets and 1 single exercise. Supersets (exercises done in succession with no rest between exercises) consisted of 2 exercises (5 exercises per day) and were repeated for 3 sets with one minute of rest between sets. Exercises performed were:incline leg pressbench pressseated rowcable hamstring curlseated shoulder pressbicep curlsskull crusherswide grip pull downmachine leg extensionplank Participants were asked to refrain from additional resistance exercise as well as aerobic exercise training. Exercise training was performed 4 d/wk (Monday, Tuesday, Thursday, and Friday). Circuit 1 consisted of the leg press, seated row, bench press, hamstring curl and planks and was repeated on Monday and Thursday. Circuit 2 consisted of shoulder press, standing bicep curls, prone skull crushers, lat pull down and leg extensions and was repeated on Tuesday and Friday of each week. Sets were performed in a drop-set fashion- i.e. until volitional failure at the set weight. To maintain repetitions within the designated repetition range, the exercise load was adjusted between sets. Reductions in exercise load between sets varied depending on the exercise performed but was approximately a 5% drop for the LR group and 10% for the HR group. All exercise sessions were individually supervised by personal trainers who instructed participants on correct form and technique. Both HR and LR groups performed 1RM testing at baseline and at weeks 3, 6, 9 and 12. 1RM tests were completed on the first day (Monday) every 3 weeks during training. Weeks that included 1RM testing (4, 7 and 10) involved only 3 prescribed RE days with 1RM testing to serve as the 4th exercise day. Participants consumed 30 grams of whey protein (BioPRO, Davisco Foods International, Le Sueur, MN) twice per day, following RE on training days to potentiate increases in MPS following training and immediately before bed to maximize increases in MPS while at rest ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/ajcn.112.055517", "ISSN" : "00029165", "PMID" : "24257722", "abstract" : "Background: The intake of whey, compared with casein and soy protein intakes, stimulates a greater acute response of muscle protein synthesis (MPS) to protein ingestion in rested and exercised muscle. Objective: We characterized the dose-response relation of postab- sorptive rates of myofibrillar MPS to increasing amounts of whey protein at rest and after exercise in resistance-trained, young men. Design: Volunteers (n = 48) consumed a standardized, high-protein (0.54 g/kg body mass) breakfast. Three hours later, a bout of uni- lateral exercise (8 3 10 leg presses and leg extensions; 80% one- repetition maximum) was performed. Volunteers ingested 0, 10, 20, or 40 g whey protein isolate immediately (w10 min) after exercise. Postabsorptive rates of myofibrillar MPS and whole-body rates of phenylalanine oxidation and urea production were measured over a 4-h postdrink period by continuous tracer infusion of labeled [13C6] phenylalanine and [15N2] urea. Results: Myofibrillar MPS (6SD) increased (P , 0.05) above 0 g whey protein (0.041 6 0.015%/h) by 49% and 56% with the in- gestion of 20 and 40 g whey protein, respectively, whereas no additional stimulation was observed with 10 g whey protein (P . 0.05). Rates of phenylalanine oxidation and urea production in- creased with the ingestion of 40 g whey protein. Conclusions: A 20-g dose of whey protein is sufficient for the maximal stimulation of postabsorptive rates of myofibrillar MPS in rested and exercised muscle ofw80-kg resistance-trained, young men. A dose of whey protein.20 g stimulates amino acid oxidation and ureagenesis. This", "author" : [ { "dropping-particle" : "", "family" : "Witard", "given" : "Oliver C.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Jackman", "given" : "Sarah R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Smith", "given" : "Kenneth", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Selby", "given" : "Anna", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tipton", "given" : "Kevin D.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "American Journal of Clinical Nutrition", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2014" ] ] }, "page" : "86-95", "title" : "Myofibrillar muscle protein synthesis rates subsequent to a meal in response to increasing doses of whey protein at rest and after resistance exercise", "type" : "article-journal", "volume" : "99" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[50]", "plainTextFormattedCitation" : "[50]", "previouslyFormattedCitation" : "[50]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[50]. On non-exercise days, participants consumed the first 30 grams in the morning and the second dose immediately before bed, similar to training days. 1.6Statistical AnalysisAll analyses were performed using SPSS (version 22.0, Chicago, IL, USA). The Shapiro- Wilk test was used to check data for normality. Baseline characteristics (body mass, height, strength and percent fat and lean mass) were compared between groups using an unpaired T-test. Strength and body composition measures were analyzed using a two-factor (group x time) mixed-model analysis of variance (ANOVA) with repetition load (between) and time (within) as the experimental variables. Significant interaction effects were further analyzed using a Tukey’s posthoc test whenever a significant interaction was found to isolate specific differences. Statistical significance was accepted when p ≤ .05. Results are presented as means ± SEM in text and graphs and as means ± SD in tables. 2.Results2.1Participant Characteristics and AnthropometricsParticipants were matched at baseline for age, height, total body mass, lean body mass (determined by DXA) and 1RM strength for leg press, bench press, leg extension and shoulder press with no differences between groups (p > 0.05; Table 2). Twelve weeks of RT resulted in a significant increase in LBM, appendicular lean mass (ALM), and leg lean mass (LLM) in the HR group (1.01 ± 0.87kg, p < .001; 0.81 ± 1.14 kg, p < 0.05; 0.66 ± 0.92 kg, p < 0.01 respectively) and the LR group (1.62 ± 1.4 kg, p < .001; 1.01 ± 1.18 kg, p < 0.001; 0.66 ± 0.99 kg, p < 0.01 respectively) with no significant interaction between groups (p < 0.05). Figure 1a represents the individual changes in LBM in the HR group and Figure 1b represents the individual changes in LBM in the LR group. VariableHR (n=24)LR (n=25)PrePost* Pre Post*Total LBM, kg 64.6 ± 8.265.4 ± 8.264.6 ± 7.066.2 ± 6.9ALM, kg 32.8 ± 4.533.6 ± 4.333.2 ± 3.534.4 ± 3.8LLM, kg 24.7 ± 4.025.2 ± 3.724.2 ± 2.724.8 ± 2.9Total fat mass, kg 19.6 ± 10.118.6 ± 9.916.8 ± 6.716.7 ± 6.4 Table 2. Participant body composition following 12 weeks of resistance exercise trainingValues are means ± SD, HR, high repetition group (20-25 repetitions per set), LR, low repetition group (8-12 repetitions per set). LBM, lean body mass; ALM, appendicular lean mass; LLM, leg lean mass. *Significantly different from pre (p < 0.05). -342900-342900Figure SEQ Figure \* ARABIC 10Figure SEQ Figure \* ARABIC 1centertopFigure 1. Individual changes in LBM in the HR(a) and LR (b) groups following 12 weeks of resistance exercise training00Figure 1. Individual changes in LBM in the HR(a) and LR (b) groups following 12 weeks of resistance exercise training2.2Strength ChangesMaximum isotonic strength for leg press, leg extension and shoulder press increased significantly in the HR group (leg press Δ = 116 ± 47 kg, p < 0.001, leg extension Δ = 29 ± 13 kg, p < 0.01, 22 ± 17 kg, p < 0.01 respectively) and the LR group (134 ± 53 kg, p < .001; 33 ± 12 kg, p < 0.01, 18 ± 34 kg, p < 0.01 respectively) following RT with no significant differences between groups (p < 0.05). Bench press 1RM increased significantly following RT in both the HR (9 ± 7 kg, p < 0.01) and in the LR (14 ± 7 kg, p < 0.01) groups; however bench press isotonic strength increased in the LR group to a greater extent than the HR group (p = 0.012). Figure 2 represents strength changes for HR and LR leg press (2a), bench press (2b), leg extension (2c) and leg press (2d). Data are summarized in Table 3. HR (n=24)LR (n=25)p-value PrePost*PrePost*Leg press 1RM, kg a357 ± 62469 ± 83357 ± 62490 ± 65>0.05Bench press 1RM, kg a97 ± 17106 ± 1997 ± 19112 ± 170.012*?Leg extension 1RM, kg a76 ± 16105 ± 16 76 ± 15109 ± 15>0.05Shoulder press 1RM, kg a92 ± 22114 ± 2491 ± 18114 ± 16>0.05Figure SEQ Figure \* ARABIC 2. Strength changes in the HR and LR groups following 12 weeks of resistance training for the leg press (a), bench press (b), leg extension (c), and shoulder press (d) exercises. Values are median ± min/max, + indicates mean. HR, high repetition group (20-25 repetitions per set), LR, low repetition group (8-12 repetitions per set). *Significantly different from baseline, ? significantly different between HR and LR.Table 3. Participant strength following 12 weeks of resistance exercise trainingValues are means ± SD, HR, high repetition group (20-25 repetitions per set), LR, low repetition group (8-12 repetitions per set). a Maximal isotonic strength measured as single best weight lifted (see METHODS for details). P value indicates differences between groups. * Significant difference from baseline (p < 0.05). ? Significantly different between HR and LR (p < 0.05).2.3Volume of Exercise Total volume (repetition x sets x load) was significantly different between groups (p < 0.05) where average volume completed per exercise session was 52893 ± 10335 kg for the HR group and 31732 ± 4317 kg for the LR group. Volume per session was calculated by taking the total volume and dividing by 45 (4 sessions x 12 weeks – 3 1RM sessions). The volume of exercise performed by the LR repetition group was on average 66% of the total load lifted by the HR group per session. Figure 3 represents the average volume of exercise performed per session. 034925Figure 3. Average volume of exercise performed per training session00Figure 3. Average volume of exercise performed per training sessionValues are median ± min/max, + indicates mean. HR, high repetition group (20-25 repetitions per set), LR, low repetition group (8-12 repetitions per set). *Significantly different between HR and LR2.4DiscussionPreviously, it has been shown that repetition load is not a primary determinant of RT-induced skeletal muscle hypertrophy in untrained males as long as volitional failure is achieved ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Schoenfeld", "given" : "Brad J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilson", "given" : "Jacob M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lowery", "given" : "Ryan P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Krieger", "given" : "James W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "id" : "ITEM-2", "issue" : "00", "issued" : { "date-parts" : [ [ "2014" ] ] }, "page" : "1-10", "title" : "Muscular adaptations in low- versus high-load resistance training : A meta-analysis", "type" : "article-journal", "volume" : "00" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6,63]", "plainTextFormattedCitation" : "[6,63]", "previouslyFormattedCitation" : "[6,63]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6,63]. The data from this study have been criticized on these points as being unique to the situation (using untrained participants) and the model (unilateral RT) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6]. The purpose of this investigation was to expand upon these findings by using a robust sample size, a between group comparison, and in experienced resistance-trained young men to determine the effects of high and low repetition range (low and high load respectively) during RT on hypertrophy and strength. We provide novel data showing that 12 weeks of supervised, high and low repetition range RT performed to volitional failure are similarly effective at inducing skeletal muscle hypertrophy in trained participants. Additionally, increases in muscular strength also were no different between groups with the exception of 1RM bench press strength that increased to a greater extent in the low repetition group (6.2%; Figure 2a). These findings confirm that high and low repetition (low and high load) training paradigms can elicit a comparable stimuli for the accretion of skeletal muscle mass and when taken together with previous reports ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1113/jphysiol.2006.116715", "ISSN" : "0022-3751", "PMID" : "16916907", "abstract" : "Skeletal muscle size is tightly regulated by the synergy between anabolic and catabolic signalling pathways which, in humans, have not been well characterized. Akt has been suggested to play a pivotal role in the regulation of skeletal muscle hypertrophy and atrophy in rodents and cells. Here we measured the amount of phospho-Akt and several of its downstream anabolic targets (glycogen synthase kinase-3beta (GSK-3beta), mTOR, p70(s6k) and 4E-BP1) and catabolic targets (Foxo1, Foxo3, atrogin-1 and MuRF1). All measurements were performed in human quadriceps muscle biopsies taken after 8 weeks of both hypertrophy-stimulating resistance training and atrophy-stimulating de-training. Following resistance training a muscle hypertrophy ( approximately 10%) and an increase in phospho-Akt, phospho-GSK-3beta and phospho-mTOR protein content were observed. This was paralleled by a decrease in Foxo1 nuclear protein content. Following the de-training period a muscle atrophy (5%), relative to the post-training muscle size, a decrease in phospho-Akt and GSK-3beta and an increase in Foxo1 were observed. Atrogin-1 and MuRF1 increased after the hypertrophy and decreased after the atrophy phases. We demonstrate, for the first time in human skeletal muscle, that the regulation of Akt and its downstream signalling pathways GSK-3beta, mTOR and Foxo1 are associated with both the skeletal muscle hypertrophy and atrophy processes.", "author" : [ { "dropping-particle" : "", "family" : "L\u00e9ger", "given" : "Bertrand", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cartoni", "given" : "Romain", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Praz", "given" : "Manu", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lamon", "given" : "S\u00e9verine", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "D\u00e9riaz", "given" : "Olivier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Crettenand", "given" : "Antoinette", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Gobelet", "given" : "Charles", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rohmer", "given" : "Paul", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Konzelmann", "given" : "Michel", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luthi", "given" : "Fran\u00e7ois", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Russell", "given" : "Aaron P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-2", "issue" : "Pt 3", "issued" : { "date-parts" : [ [ "2006", "11", "1" ] ] }, "page" : "923-33", "title" : "Akt signalling through GSK-3beta, mTOR and Foxo1 is involved in human skeletal muscle hypertrophy and atrophy.", "type" : "article-journal", "volume" : "576" }, "uris" : [ "" ] }, { "id" : "ITEM-3", "itemData" : { "DOI" : "10.1002/mus.24271", "ISSN" : "1097-4598", "PMID" : "24828840", "abstract" : "Introduction: While current exercise guidelines recommend progressive, high-intensity resistance training (RT) to promote muscle hypertrophy and strength gains, controversy exists regarding the efficacy of lighter-load RT. We compared 2 work-matched RT interventions that differed in training intensity. Methods: Fifteen women underwent 10 weeks of unilateral knee extensor RT. One leg was trained at increasing intensity (intensity leg, InL, 50-80% 1-RM), and training progression in the contralateral leg (volume leg, VoL, 50% 1-RM) was based on increasing training volumes. Quadriceps muscle size (ultrasound, DXA) and strength (isokinetic dynamometry) were assessed on 4 occasions. Results: Both training programs induced significant, yet comparable increases in muscle size (InL: +4.6-12%, VoL: +3.1-11%) and strength (InL: +10-16%, VoL: +10-14%). Discussion: Training at lower than commonly suggested intensities may be an equally effective alternative form of RT. Factors other than training intensity, such as the total mechanical work during training, may strongly affect the training response. \u00a9 2014 Wiley Periodicals, Inc.", "author" : [ { "dropping-particle" : "", "family" : "Alegre", "given" : "Luis M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aguado", "given" : "Xavier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rojas-Mart\u00edn", "given" : "Diego", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Mart\u00edn-Garc\u00eda", "given" : "Mar\u00eda", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ara", "given" : "Ignacio", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Csapo", "given" : "Robert", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Muscle & nerve", "id" : "ITEM-3", "issue" : "1", "issued" : { "date-parts" : [ [ "2015" ] ] }, "page" : "92-101", "title" : "Load-controlled moderate and high-intensity resistance training programs provoke similar strength gains in young women.", "type" : "article-journal", "volume" : "51" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6,61,71]", "plainTextFormattedCitation" : "[6,61,71]", "previouslyFormattedCitation" : "[6,61,71]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6,61,71] suggests that these effects are not contingent upon training status. 2.4.1High vs. Low Repetition RT and HypertrophyFew studies have addressed the effect of repetition load with the main outcome as hypertrophy and strength when the exercise sessions are not volume-matched (repetition x load) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1113/jphysiol.2006.116715", "ISSN" : "0022-3751", "PMID" : "16916907", "abstract" : "Skeletal muscle size is tightly regulated by the synergy between anabolic and catabolic signalling pathways which, in humans, have not been well characterized. Akt has been suggested to play a pivotal role in the regulation of skeletal muscle hypertrophy and atrophy in rodents and cells. Here we measured the amount of phospho-Akt and several of its downstream anabolic targets (glycogen synthase kinase-3beta (GSK-3beta), mTOR, p70(s6k) and 4E-BP1) and catabolic targets (Foxo1, Foxo3, atrogin-1 and MuRF1). All measurements were performed in human quadriceps muscle biopsies taken after 8 weeks of both hypertrophy-stimulating resistance training and atrophy-stimulating de-training. Following resistance training a muscle hypertrophy ( approximately 10%) and an increase in phospho-Akt, phospho-GSK-3beta and phospho-mTOR protein content were observed. This was paralleled by a decrease in Foxo1 nuclear protein content. Following the de-training period a muscle atrophy (5%), relative to the post-training muscle size, a decrease in phospho-Akt and GSK-3beta and an increase in Foxo1 were observed. Atrogin-1 and MuRF1 increased after the hypertrophy and decreased after the atrophy phases. We demonstrate, for the first time in human skeletal muscle, that the regulation of Akt and its downstream signalling pathways GSK-3beta, mTOR and Foxo1 are associated with both the skeletal muscle hypertrophy and atrophy processes.", "author" : [ { "dropping-particle" : "", "family" : "L\u00e9ger", "given" : "Bertrand", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cartoni", "given" : "Romain", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Praz", "given" : "Manu", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lamon", "given" : "S\u00e9verine", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "D\u00e9riaz", "given" : "Olivier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Crettenand", "given" : "Antoinette", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Gobelet", "given" : "Charles", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rohmer", "given" : "Paul", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Konzelmann", "given" : "Michel", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luthi", "given" : "Fran\u00e7ois", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Russell", "given" : "Aaron P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-2", "issue" : "Pt 3", "issued" : { "date-parts" : [ [ "2006", "11", "1" ] ] }, "page" : "923-33", "title" : "Akt signalling through GSK-3beta, mTOR and Foxo1 is involved in human skeletal muscle hypertrophy and atrophy.", "type" : "article-journal", "volume" : "576" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6,61]", "plainTextFormattedCitation" : "[6,61]", "previouslyFormattedCitation" : "[6,61]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6,61]. Total volume performed per exercise session, defined here as the number of repetitions performed per exercise multiplied by the sets performed, by the exercise load ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1249/01.MSS.0000121945.36635.61", "ISBN" : "0195-9131 (Print)\\r0195-9131 (Linking)", "ISSN" : "01959131", "PMID" : "15064596", "abstract" : "Progression in resistance training is a dynamic process that requires an exercise prescription process, evaluation of training progress, and careful development of target goals. The process starts with the determination of individual needs and training goals. This involves decisions regarding questions as to what muscles must be trained, injury prevention sites, metabolic demands of target training goals, etc. The single workout must then be designed reflecting these targeted program goals including the choice of exercises, order of exercise, amount of rest used between sets and exercises, number of repetitions and sets used for each exercise, and the intensity of each exercise. For progression, these variables must then be varied over time and the exercise prescription altered to maintain or advance specific training goals and to avoid overtraining. A careful system of goal targeting, exercise testing, proper exercise technique, supervision, and optimal exercise prescription all contribute to the successful implementation of a resistance training program.", "author" : [ { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and Science in Sports and Exercise", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2004" ] ] }, "page" : "674-688", "title" : "Fundamentals of Resistance Training: Progression and Exercise Prescription", "type" : "article-journal", "volume" : "36" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[78]", "plainTextFormattedCitation" : "[78]", "previouslyFormattedCitation" : "[78]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[78]. It is evident that when exercise sessions are volume matched, volitional failure is not reached and as such, low repetition exercise is often delineated as providing the greatest beneficial response ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.90538.2008", "ISBN" : "8750-7587 (Print)", "ISSN" : "8750-7587", "PMID" : "18787090", "abstract" : "Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60 degrees /s. Quadriceps muscle cross-sectional area increased (P < 0.05) 8 +/- 1% and 3 +/- 1% in HL and LL legs, respectively, with a greater gain in HL than LL (P < 0.05). Likewise, 1RM strength increased (P < 0.001) in both legs (HL: 36 +/- 5%, LL: 19 +/- 2%), albeit more so with HL (P < 0.01). Isokinetic 60 degrees /s muscle strength improved by 13 +/- 5% (P < 0.05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.", "author" : [ { "dropping-particle" : "", "family" : "Holm", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Reitelseder", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pedersen", "given" : "T G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Doessing", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Petersen", "given" : "S G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Flyvbjerg", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Andersen", "given" : "J L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aagaard", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kjaer", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Applied Physiology", "id" : "ITEM-1", "issue" : "5", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "1454-1461", "title" : "Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity.", "type" : "article-journal", "volume" : "105" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-2", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5,64]", "plainTextFormattedCitation" : "[5,64]", "previouslyFormattedCitation" : "[5,64]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5,64]. Following 12 weeks of progressive RT we found that both the HR and LR groups showed significant gains in whole body lean mass gains of (Table 2) with no differences between groups. Total volume performed in the LR group was approximately 66% of the total exercise performed by the HR group and therefore, we hypothesize that the increased work performed by the HR group was likely part of what contributed to the similar adaptations seen in the LR group. Previous studies have focused on the use of specific repetition ranges that progress similarly between groups with the aim of matching total volume lifted ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). 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All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. 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The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60 degrees /s. Quadriceps muscle cross-sectional area increased (P < 0.05) 8 +/- 1% and 3 +/- 1% in HL and LL legs, respectively, with a greater gain in HL than LL (P < 0.05). Likewise, 1RM strength increased (P < 0.001) in both legs (HL: 36 +/- 5%, LL: 19 +/- 2%), albeit more so with HL (P < 0.01). Isokinetic 60 degrees /s muscle strength improved by 13 +/- 5% (P < 0.05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.", "author" : [ { "dropping-particle" : "", "family" : "Holm", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Reitelseder", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pedersen", "given" : "T G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Doessing", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Petersen", "given" : "S G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Flyvbjerg", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Andersen", "given" : "J L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aagaard", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kjaer", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Applied Physiology", "id" : "ITEM-2", "issue" : "5", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "1454-1461", "title" : "Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity.", "type" : "article-journal", "volume" : "105" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5,64]", "plainTextFormattedCitation" : "[5,64]", "previouslyFormattedCitation" : "[5,64]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5,64]. More often these same studies had participants lifting weights in the lower repetition (higher load) range to fatigue and then matching the volume lifted in that condition to the higher repetition (lower load) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.90538.2008", "ISBN" : "8750-7587 (Print)", "ISSN" : "8750-7587", "PMID" : "18787090", "abstract" : "Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60 degrees /s. Quadriceps muscle cross-sectional area increased (P < 0.05) 8 +/- 1% and 3 +/- 1% in HL and LL legs, respectively, with a greater gain in HL than LL (P < 0.05). Likewise, 1RM strength increased (P < 0.001) in both legs (HL: 36 +/- 5%, LL: 19 +/- 2%), albeit more so with HL (P < 0.01). Isokinetic 60 degrees /s muscle strength improved by 13 +/- 5% (P < 0.05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.", "author" : [ { "dropping-particle" : "", "family" : "Holm", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Reitelseder", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pedersen", "given" : "T G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Doessing", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Petersen", "given" : "S G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Flyvbjerg", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Andersen", "given" : "J L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aagaard", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kjaer", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Applied Physiology", "id" : "ITEM-1", "issue" : "5", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "1454-1461", "title" : "Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity.", "type" : "article-journal", "volume" : "105" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1111/j.1475-097X.1996.tb00727.x", "ISBN" : "1365-2281", "ISSN" : "0144-5979", "PMID" : "8842574", "abstract" : "The effects of 52 weeks resistance training at one of two exercise intensities on thigh muscle strength, fiber cross-sectional area (CSA), and tissue composition were studied in healthy 65-79-year-old women. Subjects were assigned to either a control (CO), high-intensity (HI) or low-intensity (LO) training group. Exercise regimens consisted of three sets of leg press, knee extension, and knee flexion exercises, 3 days/week, at either 80% of one-repetition maximum (1-RM) for seven repetitions (HI) or 40% of 1-RM for 14 repetitions (LO). Dynamic muscle strength was evaluated by 1-RM, thigh lean tissue mass (LTM), fat mass, and bone mineral density (BMD, g/cm2) by dual energy X-ray absorptiometry, and fiber CSA of vastus lateralis m. by histomorphometry. Muscle strength increased, on average (+/- SEM), by 59.4 +/- 7.9% and 41.5 +/- 7.9% for HI and LO, respectively, compared to 1.3 +/- 4.8% in CO (P = 0.0001). Type I fiber CSA increased over time (P < 0.05) in both exercise groups, with a trend for increased type II area (HI, P = 0.06; LO, P = 0.11). There was no significant effect of either exercise program on thigh tissue composition, except for BMD at the 1/3 site (middle third of the femur), where LO and CO groups experienced a decline (P < 0.05) of -2.2 +/- 0.5% and -1.8 +/- 0.6%, respectively, while HI maintained BMD (+1.0 +/- 1.0%). Both training programs produced significant gains in thigh muscle strength, which were associated with fiber hypertrophy, although these did not translate into appreciable alterations in thigh tissue composition.", "author" : [ { "dropping-particle" : "", "family" : "Taffe", "given" : "D R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pruitt", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pyka", "given" : "G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Guido", "given" : "D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Marcus", "given" : "R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Clinical physiology (Oxford, England)", "id" : "ITEM-2", "issued" : { "date-parts" : [ [ "1996" ] ] }, "page" : "381-392", "title" : "Comparative effects of high- and low-intensity resistance training on thigh muscle strength, fiber area, and tissue composition in elderly women.", "type" : "article-journal", "volume" : "16" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[64,73]", "plainTextFormattedCitation" : "[64,73]", "previouslyFormattedCitation" : "[64,73]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[64,73]. Work from our group examining the MPS response in such a matching condition clearly indicates that higher repetition-lower load volume-matched to a lower repetition-higher load group produces a substantially inferior MPS response ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/jn.110.135038\rjn.110.135038 [pii]", "ISBN" : "1541-6100 (Electronic)\r0022-3166 (Linking)", "PMID" : "21289204", "abstract" : "We aimed to determine whether an exercise-mediated enhancement of muscle protein synthesis to feeding persisted 24 h after resistance exercise. We also determined the impact of different exercise intensities (90% or 30% maximal strength) or contraction volume (work-matched or to failure) on the response at 24 h of recovery. Fifteen men (21 +/- 1 y, BMI = 24.1 +/- 0.8 kg . m(-2)) received a primed, constant infusion of l-[ring-(13)C(6)]phenylalanine to measure muscle protein synthesis after protein feeding at rest (FED; 15 g whey protein) and 24 h after resistance exercise (EX-FED). Participants performed unilateral leg exercises: 1) 4 sets at 90% of maximal strength to failure (90FAIL); 2) 30% work-matched to 90FAIL (30WM); or 3) 30% to failure (30FAIL). Regardless of condition, rates of mixed muscle protein and sarcoplasmic protein synthesis were similarly stimulated at FED and EX-FED. In contrast, protein ingestion stimulated rates of myofibrillar protein synthesis above fasting rates by 0.016 +/- 0.002%/h and the response was enhanced 24 h after resistance exercise, but only in the 90FAIL and 30FAIL conditions, by 0.038 +/- 0.012 and 0.041 +/- 0.010, respectively. Phosphorylation of protein kinase B on Ser473 was greater than FED at EX-FED only in 90FAIL, whereas phosphorylation of mammalian target of rapamycin on Ser2448 was significantly increased at EX-FED above FED only in the 30FAIL condition. Our results suggest that resistance exercise performed until failure confers a sensitizing effect on human skeletal muscle for at least 24 h that is specific to the myofibrillar protein fraction.", "author" : [ { "dropping-particle" : "", "family" : "Burd", "given" : "N A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "D W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moore", "given" : "D R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Atherton", "given" : "P J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staples", "given" : "A W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Prior", "given" : "T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tang", "given" : "J E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rennie", "given" : "M J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "S K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Nutr", "edition" : "2011/02/04", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2011" ] ] }, "language" : "eng", "page" : "568-573", "title" : "Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men", "type" : "article-journal", "volume" : "141" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[38]", "plainTextFormattedCitation" : "[38]", "previouslyFormattedCitation" : "[38]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[38]. In contrast, we showed that lower loads, when lifted to fatigue (i.e., a greater volume than the higher load condition) results in a superior stimulation of MPS ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.3945/jn.110.135038\rjn.110.135038 [pii]", "ISBN" : "1541-6100 (Electronic)\r0022-3166 (Linking)", "PMID" : "21289204", "abstract" : "We aimed to determine whether an exercise-mediated enhancement of muscle protein synthesis to feeding persisted 24 h after resistance exercise. We also determined the impact of different exercise intensities (90% or 30% maximal strength) or contraction volume (work-matched or to failure) on the response at 24 h of recovery. Fifteen men (21 +/- 1 y, BMI = 24.1 +/- 0.8 kg . m(-2)) received a primed, constant infusion of l-[ring-(13)C(6)]phenylalanine to measure muscle protein synthesis after protein feeding at rest (FED; 15 g whey protein) and 24 h after resistance exercise (EX-FED). Participants performed unilateral leg exercises: 1) 4 sets at 90% of maximal strength to failure (90FAIL); 2) 30% work-matched to 90FAIL (30WM); or 3) 30% to failure (30FAIL). Regardless of condition, rates of mixed muscle protein and sarcoplasmic protein synthesis were similarly stimulated at FED and EX-FED. In contrast, protein ingestion stimulated rates of myofibrillar protein synthesis above fasting rates by 0.016 +/- 0.002%/h and the response was enhanced 24 h after resistance exercise, but only in the 90FAIL and 30FAIL conditions, by 0.038 +/- 0.012 and 0.041 +/- 0.010, respectively. Phosphorylation of protein kinase B on Ser473 was greater than FED at EX-FED only in 90FAIL, whereas phosphorylation of mammalian target of rapamycin on Ser2448 was significantly increased at EX-FED above FED only in the 30FAIL condition. Our results suggest that resistance exercise performed until failure confers a sensitizing effect on human skeletal muscle for at least 24 h that is specific to the myofibrillar protein fraction.", "author" : [ { "dropping-particle" : "", "family" : "Burd", "given" : "N A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "D W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moore", "given" : "D R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Atherton", "given" : "P J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staples", "given" : "A W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Prior", "given" : "T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Tang", "given" : "J E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rennie", "given" : "M J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "S K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "S M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Nutr", "edition" : "2011/02/04", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2011" ] ] }, "language" : "eng", "page" : "568-573", "title" : "Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men", "type" : "article-journal", "volume" : "141" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[38]", "plainTextFormattedCitation" : "[38]", "previouslyFormattedCitation" : "[38]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[38] and equivalent hypertrophy ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6]. Thus, in the current protocol our participants performed their exercise regardless of group assignment to reach volitional fatigue and thus it was not a volume-matched protocol. As mentioned previously, the performance of RE to volitional muscular fatigue is essential, based on our data ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1371/journal.pone.0012033", "ISBN" : "1932-6203 (Electronic)\n1932-6203 (Linking)", "ISSN" : "1932-6203", "PMID" : "20711498", "abstract" : "BACKGROUND: We aimed to determine the effect of resistance exercise intensity (%1 repetition maximum-1RM) and volume on muscle protein synthesis, anabolic signaling, and myogenic gene expression. METHODOLOGY/PRINCIPAL FINDINGS: Fifteen men (21+/-1 years; BMI=24.1+/-0.8 kg/m2) performed 4 sets of unilateral leg extension exercise at different exercise loads and/or volumes: 90% of repetition maximum (1RM) until volitional failure (90FAIL), 30% 1RM work-matched to 90%FAIL (30WM), or 30% 1RM performed until volitional failure (30FAIL). Infusion of [ring-13C6] phenylalanine with biopsies was used to measure rates of mixed (MIX), myofibrillar (MYO), and sarcoplasmic (SARC) protein synthesis at rest, and 4 h and 24 h after exercise. Exercise at 30WM induced a significant increase above rest in MIX (121%) and MYO (87%) protein synthesis at 4 h post-exercise and but at 24 h in the MIX only. The increase in the rate of protein synthesis in MIX and MYO at 4 h post-exercise with 90FAIL and 30FAIL was greater than 30WM, with no difference between these conditions; however, MYO remained elevated (199%) above rest at 24 h only in 30FAIL. There was a significant increase in AktSer473 at 24h in all conditions (P=0.023) and mTORSer2448 phosphorylation at 4 h post-exercise (P=0.025). Phosporylation of Erk1/2Tyr202/204, p70S6KThr389, and 4E-BP1Thr37/46 increased significantly (P<0.05) only in the 30FAIL condition at 4 h post-exercise, whereas, 4E-BP1Thr37/46 phosphorylation was greater 24 h after exercise than at rest in both 90FAIL (237%) and 30FAIL (312%) conditions. Pax7 mRNA expression increased at 24 h post-exercise (P=0.02) regardless of condition. The mRNA expression of MyoD and myogenin were consistently elevated in the 30FAIL condition. CONCLUSIONS/SIGNIFICANCE: These results suggest that low-load high volume resistance exercise is more effective in inducing acute muscle anabolism than high-load low volume or work matched resistance exercise modes.", "author" : [ { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staples", "given" : "Aaron W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Atherton", "given" : "Philip J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Jeff M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Holwerda", "given" : "Andrew M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Parise", "given" : "Gianni", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rennie", "given" : "Michael J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "PloS one", "edition" : "2010/08/17", "id" : "ITEM-2", "issue" : "8", "issued" : { "date-parts" : [ [ "2010", "1" ] ] }, "language" : "eng", "note" : "From Duplicate 2 ( ", "page" : "e12033", "title" : "Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men.", "type" : "article-journal", "volume" : "5" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6,79]", "plainTextFormattedCitation" : "[6,79]", "previouslyFormattedCitation" : "[6,79]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6,79], as it is necessary for maximal motor unit recruitment and thus hypertrophy of muscle fibres innervated by both large and small MUs ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "ISBN" : "0022-0949 (Print)\\r0022-0949 (Linking)", "ISSN" : "0022-0949", "PMID" : "3161974", "abstract" : "Orderly, size-related recruitment of motoneurones (MNs) illustrates how hundreds of cells operate as a functional entity to produce a highly deterministic output. The coherent action of the pool depends largely on the distribution of input to its members through the connections of afferent fibres. Three types of spike-triggered averaging have been utilized to study these connections. Impulses in individual Ia afferents elicit excitatory postsynaptic potentials ('single-fibre' EPSPs) in about 80% of homonymous MNs. After spinal transection 100% may respond, suggesting that Ia fibres project anatomically to all homonymous MNs. Functionally absent Ia connections are due to transmission failure. The sum of all the EPSPs elicited in a large population of MNs was recorded electrotonically from ventral roots. The mean amplitudes of these 'postsynaptic population potentials' (PSPPs) were correlated with the conduction velocities (CVs) of the Ia or spindle group II fibres. The greater the distance between the spinal entry point of a Ia fibre and the ventral root, the smaller was the PSPP. Tape recording of multiple afferents and the responses of up to 24 MNs permitted study of as many as 264 possible connections in a single, acute experiment. Construction of wiring diagrams and connectivity matrices from the data showed that functional connectivity is influenced by afferent fibre size, the effect of branching on fibre size, MN size and probably transmission failure, but that on a cell-to-cell level, connectivity does not follow strict, deterministic rules. The results raise the question of how probabilistic connections between afferent fibres and MNs give rise to deterministic outputs from the whole pool.", "author" : [ { "dropping-particle" : "", "family" : "Henneman", "given" : "E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of experimental biology", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "1985" ] ] }, "page" : "105-112", "title" : "The size-principle: a deterministic output emerges from a set of probabilistic connections.", "type" : "article-journal", "volume" : "115" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-2", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6,66]", "plainTextFormattedCitation" : "[6,66]", "previouslyFormattedCitation" : "[6,66]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6,66]. Based on previous results ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1152/japplphysiol.90538.2008", "ISBN" : "8750-7587 (Print)", "ISSN" : "8750-7587", "PMID" : "18787090", "abstract" : "Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60 degrees /s. Quadriceps muscle cross-sectional area increased (P < 0.05) 8 +/- 1% and 3 +/- 1% in HL and LL legs, respectively, with a greater gain in HL than LL (P < 0.05). Likewise, 1RM strength increased (P < 0.001) in both legs (HL: 36 +/- 5%, LL: 19 +/- 2%), albeit more so with HL (P < 0.01). Isokinetic 60 degrees /s muscle strength improved by 13 +/- 5% (P < 0.05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.", "author" : [ { "dropping-particle" : "", "family" : "Holm", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Reitelseder", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pedersen", "given" : "T G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Doessing", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Petersen", "given" : "S G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Flyvbjerg", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Andersen", "given" : "J L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aagaard", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kjaer", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Applied Physiology", "id" : "ITEM-2", "issue" : "5", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "1454-1461", "title" : "Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity.", "type" : "article-journal", "volume" : "105" }, "uris" : [ "" ] }, { "id" : "ITEM-3", "itemData" : { "DOI" : "10.1097/00005768-200011000-00020", "ISBN" : "0195-9131 (Print)\\r0195-9131 (Linking)", "ISSN" : "0195-9131", "PMID" : "11079527", "abstract" : "PURPOSE: The purpose of this study was to compare the effects of a high-load (80%, 1-repetition maximum (RM), 8 reps) and a high-repetition (40%, 1-RM, 16 reps) resistance training protocol on muscular strength and bone mineral density (BMD) in early postmenopausal, estrogen-deficient women. The 6-month programs were matched initially for training volume (3 sets, 3 d x wk(-1)) for 12 exercises selected to specifically load the spine and hip. METHODS: Subjects included 25 women (41-60 yr) who were matched by spine BMD then randomly assigned to either the high-load (HL, N = 10), high-repetition (HR, N = 7), or control (C, N = 8) groups. Dietary calcium intakes were supplemented to approximately 1500 mg x d(-1). Total body, spine, and hip BMD (DXA, Lunar Model DPX-IQ), upper and lower body muscular strength, and biochemical markers of bone turnover were measured at baseline and after 6 months of training. RESULTS: There were no group differences in the baseline measures. Both training groups showed similar increases in biceps (20%) and rectus femoris (28-33%) cross-sectional areas, in lower body strength (approximately 30%) and in hip strength (37-40%). HL showed greater improvements in upper body strength (HL 25%, HR 16%). Neither training group experienced significant increases in spine or hip BMD, although the HL total body BMD tended to decrease (-1.1%+/-0.4, P = 0.054) after training. Osteocalcin tended to increase (P = 0.08) in all groups after training, and the % change in osteocalcin was positively related to % changes in the total hip (r = 0.41, P = 0.048) and the trochanter (r = 0.42, P = 0.04) BMD. CONCLUSION: The high-load and high-repetition resistance training protocols were both effective in improving muscular strength and size in postmenopausal women, indicating low-intensity resistance training can be beneficial for the muscular fitness in women for whom high-intensity exercise is contraindicated.", "author" : [ { "dropping-particle" : "", "family" : "Bemben", "given" : "D a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Fetters", "given" : "N L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Bemben", "given" : "M G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Nabavi", "given" : "N", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Koh", "given" : "E T", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and science in sports and exercise", "id" : "ITEM-3", "issue" : "27", "issued" : { "date-parts" : [ [ "2000" ] ] }, "page" : "1949-1957", "title" : "Musculoskeletal responses to high- and low-intensity resistance training in early postmenopausal women.", "type" : "article-journal", "volume" : "32" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5,64,72]", "plainTextFormattedCitation" : "[5,64,72]", "previouslyFormattedCitation" : "[5,64,72]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5,64,72], when high and low load protocols are not performed until volitional fatigue (i.e. not volume equated), it is evident that equivalent hypertrophy is unlikely to occur. For example, Holm and colleagues examined 12 untrained young men who performed volume-matched unilateral RT where one leg performed low repetition RT (70% of 1RM for 8 reps) while the other leg performed high repetition RT (16% of 1RM for 36 reps) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.90538.2008", "ISBN" : "8750-7587 (Print)", "ISSN" : "8750-7587", "PMID" : "18787090", "abstract" : "Muscle mass accretion is accomplished by heavy-load resistance training. The effect of light-load resistance exercise has been far more sparsely investigated with regard to potential effect on muscle size and contractile strength. We applied a resistance exercise protocol in which the same individual trained one leg at 70% of one-repetition maximum (1RM) (heavy load, HL) while training the other leg at 15.5% 1RM (light load, LL). Eleven sedentary men (age 25 +/- 1 yr) trained for 12 wk at three times/week. Before and after the intervention muscle hypertrophy was determined by magnetic resonance imaging, muscle biopsies were obtained bilaterally from vastus lateralis for determination of myosin heavy chain (MHC) composition, and maximal muscle strength was assessed by 1RM testing and in an isokinetic dynamometer at 60 degrees /s. Quadriceps muscle cross-sectional area increased (P < 0.05) 8 +/- 1% and 3 +/- 1% in HL and LL legs, respectively, with a greater gain in HL than LL (P < 0.05). Likewise, 1RM strength increased (P < 0.001) in both legs (HL: 36 +/- 5%, LL: 19 +/- 2%), albeit more so with HL (P < 0.01). Isokinetic 60 degrees /s muscle strength improved by 13 +/- 5% (P < 0.05) in HL but remained unchanged in LL (4 +/- 5%, not significant). Finally, MHC IIX protein expression was decreased with HL but not LL, despite identical total workload in HL and LL. Our main finding was that LL resistance training was sufficient to induce a small but significant muscle hypertrophy in healthy young men. However, LL resistance training was inferior to HL training in evoking adaptive changes in muscle size and contractile strength and was insufficient to induce changes in MHC composition.", "author" : [ { "dropping-particle" : "", "family" : "Holm", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Reitelseder", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pedersen", "given" : "T G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Doessing", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Petersen", "given" : "S G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Flyvbjerg", "given" : "A", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Andersen", "given" : "J L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aagaard", "given" : "P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kjaer", "given" : "M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Applied Physiology", "id" : "ITEM-1", "issue" : "5", "issued" : { "date-parts" : [ [ "2008" ] ] }, "page" : "1454-1461", "title" : "Changes in muscle size and MHC composition in response to resistance exercise with heavy and light loading intensity.", "type" : "article-journal", "volume" : "105" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[64]", "plainTextFormattedCitation" : "[64]", "previouslyFormattedCitation" : "[64]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[64]. They found that low repetition (high load) resistance exercise resulted in a significantly greater increase in muscle CSA (7.6%) compared to the high repetition group (2.6%). These findings are similar to those of Campos and colleagues who compared young, untrained men performing either 9-11 repetitions per set or 20-28 repetitions per set that were volume equated. They found that following 8 weeks of progressive RT that the group performing the low repetitions (9-11 repetitions per set) had a significant increase in type I, type IIA and type IIB fibre CSA of 12%, 19%, and 26% respectively. In contrast, muscle fibre CSA did not increase in the high repetition group ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5]", "plainTextFormattedCitation" : "[5]", "previouslyFormattedCitation" : "[5]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5]. The non-significant increase in fibre CSA reported by Campos et al ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5]", "plainTextFormattedCitation" : "[5]", "previouslyFormattedCitation" : "[5]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5] is in contrast to work from our group where total exercise volume was not matched between groups performing RE lifting at 30% of 1RM or 80% of 1RM to volitional muscular failure for 10 wk ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6]. In this model it was identified that groups performing 30% of 1RM for 3 sets to failure, and 80% for 3 sets to failure, achieved similar increases in fibre CSA in type I and type II fibres (17 ± 4% and 16 ± 5%; 30 ± 12% and 18 ± 8%, respectively) with no significant differences between groups. These changes in fibre CSA translated to similar training-induced increases in quadriceps muscle volume of approximately 7% in both groups ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6]. Together these findings suggest that the capacity for hypertrophic response is not dictated by the exercise load being lifted, but rather by ensuring complete motor unit recruitment and fatigue, which can be achieved by lifting a load, be it heavy or light, to the point of momentary muscle fatigue. Muscle hypertrophy occurs as a result of short periods where the rates of MPS are greater than that of MPB that summed over time lead to hypertrophy ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1017/S0007114512002516", "ISBN" : "1111111111", "ISSN" : "0007-1145", "PMID" : "23107527", "abstract" : "Dietary guidelines from a variety of sources are generally congruent that an adequate dietary protein intake for persons over the age of 19 is between 0\u00b78-0\u00b79 g protein/kg body weight/d. According to the US/Canadian Dietary Reference Intakes, the RDA for protein of 0\u00b78 g protein/kg/d is \"...the average daily intake level that is sufficient to meet the nutrient requirement of nearly all [~98 %]\u2026 healthy individuals...\" The panel also states that \"...no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise.\" These recommendations are in contrast to recommendations from the US and Canadian Dietetic Association: \"Protein recommendations for endurance and strength trained athletes range from 1\u00b72 to 1\u00b77 g/kg/d.\" The disparity between those setting dietary protein requirements and those who might be considered to be making practical recommendations for athletes is substantial. This may reflect a situation where an adaptive advantage of protein intakes higher than recommended protein requirements exists. That population protein requirements are still based on nitrogen balance may also be a point of contention since achieving balanced nitrogen intake and excretion likely means little to an athlete who has the primary goal of exercise performance. The goal of the present review is to critically analyse evidence from both acute and chronic dietary protein-based studies in which athletic performance, or correlates thereof, have been measured. An attempt will be made to distinguish between protein requirements set by data from nitrogen balance studies, and a potential adaptive 'advantage' for athletes of dietary protein in excess of the RDA.", "author" : [ { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "British Journal of Nutrition", "id" : "ITEM-1", "issue" : "S2", "issued" : { "date-parts" : [ [ "2012" ] ] }, "page" : "S158-S167", "title" : "Dietary protein requirements and adaptive advantages in athletes", "type" : "article-journal", "volume" : "108" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[26]", "plainTextFormattedCitation" : "[26]", "previouslyFormattedCitation" : "[26]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[26]. Resistance exercise is a potent stimulator of MPS, especially when protein is consumed in the peri-workout period ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00726-006-0398-7", "ISBN" : "0939-4451", "ISSN" : "09394451", "PMID" : "16988909", "abstract" : "This study examined 10 wks of resistance training and the ingestion of supplemental protein and amino acids on muscle performance and markers of muscle anabolism. Nineteen untrained males were randomly assigned to supplement groups containing either 20 g protein (14 g whey and casein protein, 6 g free amino acids) or 20 g dextrose placebo ingested 1 h before and after exercise for a total of 40 g/d. Participants exercised 4 times/wk using 3 sets of 6-8 repetitions at 85-90% of the one repetition maximum. Data were analyzed with two-way ANOVA (p < 0.05). The protein supplement resulted in greater increases in total body mass, fat-free mass, thigh mass, muscle strength, serum IGF-1, IGF-1 mRNA, MHC I and IIa expression, and myofibrillar protein. Ten-wks of resistance training with 20 g protein and amino acids ingested 1 h before and after exercise is more effective than carbohydrate placebo in up-regulating markers of muscle protein synthesis and anabolism along with subsequent improvements in muscle performance.", "author" : [ { "dropping-particle" : "", "family" : "Willoughby", "given" : "D. S.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Stout", "given" : "J. R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wilborn", "given" : "C. D.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Amino Acids", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2007" ] ] }, "page" : "467-477", "title" : "Effects of resistance training and protein plus amino acid supplementation on muscle anabolism, mass, and strength", "type" : "article-journal", "volume" : "32" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[39]", "plainTextFormattedCitation" : "[39]", "previouslyFormattedCitation" : "[39]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[39]. Differences in the acute response of MPS to varying RE loads have only been investigated once, to our knowledge. Burd and colleagues, had participants perform either 90% of their one repetition maximum (1RM) to failure, 30% of their 1RM which was work matched to the 90% of 1RM, or finally 30% of 1RM to failure. Measurements were taken up to 24 hours following the bout of RE and demonstrated that although all exercise loads were able to increase MPS above rested levels, the limbs performing exercise to failure were able to increase MPS above the work matched condition regardless of load. Furthermore, it was only the limbs performing 30% to failure that showed a persistent (24h after the RE bout) stimulation of myofibrillar MPS ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1371/journal.pone.0012033", "ISBN" : "1932-6203 (Electronic)\n1932-6203 (Linking)", "ISSN" : "1932-6203", "PMID" : "20711498", "abstract" : "BACKGROUND: We aimed to determine the effect of resistance exercise intensity (%1 repetition maximum-1RM) and volume on muscle protein synthesis, anabolic signaling, and myogenic gene expression. METHODOLOGY/PRINCIPAL FINDINGS: Fifteen men (21+/-1 years; BMI=24.1+/-0.8 kg/m2) performed 4 sets of unilateral leg extension exercise at different exercise loads and/or volumes: 90% of repetition maximum (1RM) until volitional failure (90FAIL), 30% 1RM work-matched to 90%FAIL (30WM), or 30% 1RM performed until volitional failure (30FAIL). Infusion of [ring-13C6] phenylalanine with biopsies was used to measure rates of mixed (MIX), myofibrillar (MYO), and sarcoplasmic (SARC) protein synthesis at rest, and 4 h and 24 h after exercise. Exercise at 30WM induced a significant increase above rest in MIX (121%) and MYO (87%) protein synthesis at 4 h post-exercise and but at 24 h in the MIX only. The increase in the rate of protein synthesis in MIX and MYO at 4 h post-exercise with 90FAIL and 30FAIL was greater than 30WM, with no difference between these conditions; however, MYO remained elevated (199%) above rest at 24 h only in 30FAIL. There was a significant increase in AktSer473 at 24h in all conditions (P=0.023) and mTORSer2448 phosphorylation at 4 h post-exercise (P=0.025). Phosporylation of Erk1/2Tyr202/204, p70S6KThr389, and 4E-BP1Thr37/46 increased significantly (P<0.05) only in the 30FAIL condition at 4 h post-exercise, whereas, 4E-BP1Thr37/46 phosphorylation was greater 24 h after exercise than at rest in both 90FAIL (237%) and 30FAIL (312%) conditions. Pax7 mRNA expression increased at 24 h post-exercise (P=0.02) regardless of condition. The mRNA expression of MyoD and myogenin were consistently elevated in the 30FAIL condition. CONCLUSIONS/SIGNIFICANCE: These results suggest that low-load high volume resistance exercise is more effective in inducing acute muscle anabolism than high-load low volume or work matched resistance exercise modes.", "author" : [ { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staples", "given" : "Aaron W", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Atherton", "given" : "Philip J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Jeff M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Moore", "given" : "Daniel R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Holwerda", "given" : "Andrew M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Parise", "given" : "Gianni", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rennie", "given" : "Michael J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "PloS one", "edition" : "2010/08/17", "id" : "ITEM-1", "issue" : "8", "issued" : { "date-parts" : [ [ "2010", "1" ] ] }, "language" : "eng", "note" : "From Duplicate 2 ( ", "page" : "e12033", "title" : "Low-load high volume resistance exercise stimulates muscle protein synthesis more than high-load low volume resistance exercise in young men.", "type" : "article-journal", "volume" : "5" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[79]", "plainTextFormattedCitation" : "[79]", "previouslyFormattedCitation" : "[79]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[79]. Given this knowledge it is therefore not surprising that our results reflect similar increases in muscle hypertrophy between intervention groups. 2.4.2High vs. Low Repetition Resistance Exercise and StrengthIn addition to similar increases in muscle size, high and low repetition progressive RT resulted in similar increases in muscular strength between groups following the 12-week intervention. Specifically, both HR and LR increased leg press (31% vs 37%), leg extension (38% vs 43%) and shoulder press (23% vs 25%) 1 RM with no differences between groups. However, while both groups increased chest press 1 RM, the increase was greater in the LR as compared with the HR group (15% vs 9%). Current literature supports the use of both low loads (high reps) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1113/jphysiol.2006.116715", "ISSN" : "0022-3751", "PMID" : "16916907", "abstract" : "Skeletal muscle size is tightly regulated by the synergy between anabolic and catabolic signalling pathways which, in humans, have not been well characterized. Akt has been suggested to play a pivotal role in the regulation of skeletal muscle hypertrophy and atrophy in rodents and cells. Here we measured the amount of phospho-Akt and several of its downstream anabolic targets (glycogen synthase kinase-3beta (GSK-3beta), mTOR, p70(s6k) and 4E-BP1) and catabolic targets (Foxo1, Foxo3, atrogin-1 and MuRF1). All measurements were performed in human quadriceps muscle biopsies taken after 8 weeks of both hypertrophy-stimulating resistance training and atrophy-stimulating de-training. Following resistance training a muscle hypertrophy ( approximately 10%) and an increase in phospho-Akt, phospho-GSK-3beta and phospho-mTOR protein content were observed. This was paralleled by a decrease in Foxo1 nuclear protein content. Following the de-training period a muscle atrophy (5%), relative to the post-training muscle size, a decrease in phospho-Akt and GSK-3beta and an increase in Foxo1 were observed. Atrogin-1 and MuRF1 increased after the hypertrophy and decreased after the atrophy phases. We demonstrate, for the first time in human skeletal muscle, that the regulation of Akt and its downstream signalling pathways GSK-3beta, mTOR and Foxo1 are associated with both the skeletal muscle hypertrophy and atrophy processes.", "author" : [ { "dropping-particle" : "", "family" : "L\u00e9ger", "given" : "Bertrand", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Cartoni", "given" : "Romain", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Praz", "given" : "Manu", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Lamon", "given" : "S\u00e9verine", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "D\u00e9riaz", "given" : "Olivier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Crettenand", "given" : "Antoinette", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Gobelet", "given" : "Charles", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rohmer", "given" : "Paul", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Konzelmann", "given" : "Michel", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luthi", "given" : "Fran\u00e7ois", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Russell", "given" : "Aaron P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "The Journal of physiology", "id" : "ITEM-1", "issue" : "Pt 3", "issued" : { "date-parts" : [ [ "2006", "11", "1" ] ] }, "page" : "923-33", "title" : "Akt signalling through GSK-3beta, mTOR and Foxo1 is involved in human skeletal muscle hypertrophy and atrophy.", "type" : "article-journal", "volume" : "576" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1111/j.1475-097X.1996.tb00727.x", "ISBN" : "1365-2281", "ISSN" : "0144-5979", "PMID" : "8842574", "abstract" : "The effects of 52 weeks resistance training at one of two exercise intensities on thigh muscle strength, fiber cross-sectional area (CSA), and tissue composition were studied in healthy 65-79-year-old women. Subjects were assigned to either a control (CO), high-intensity (HI) or low-intensity (LO) training group. Exercise regimens consisted of three sets of leg press, knee extension, and knee flexion exercises, 3 days/week, at either 80% of one-repetition maximum (1-RM) for seven repetitions (HI) or 40% of 1-RM for 14 repetitions (LO). Dynamic muscle strength was evaluated by 1-RM, thigh lean tissue mass (LTM), fat mass, and bone mineral density (BMD, g/cm2) by dual energy X-ray absorptiometry, and fiber CSA of vastus lateralis m. by histomorphometry. Muscle strength increased, on average (+/- SEM), by 59.4 +/- 7.9% and 41.5 +/- 7.9% for HI and LO, respectively, compared to 1.3 +/- 4.8% in CO (P = 0.0001). Type I fiber CSA increased over time (P < 0.05) in both exercise groups, with a trend for increased type II area (HI, P = 0.06; LO, P = 0.11). There was no significant effect of either exercise program on thigh tissue composition, except for BMD at the 1/3 site (middle third of the femur), where LO and CO groups experienced a decline (P < 0.05) of -2.2 +/- 0.5% and -1.8 +/- 0.6%, respectively, while HI maintained BMD (+1.0 +/- 1.0%). Both training programs produced significant gains in thigh muscle strength, which were associated with fiber hypertrophy, although these did not translate into appreciable alterations in thigh tissue composition.", "author" : [ { "dropping-particle" : "", "family" : "Taffe", "given" : "D R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pruitt", "given" : "L", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pyka", "given" : "G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Guido", "given" : "D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Marcus", "given" : "R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Clinical physiology (Oxford, England)", "id" : "ITEM-2", "issued" : { "date-parts" : [ [ "1996" ] ] }, "page" : "381-392", "title" : "Comparative effects of high- and low-intensity resistance training on thigh muscle strength, fiber area, and tissue composition in elderly women.", "type" : "article-journal", "volume" : "16" }, "uris" : [ "" ] }, { "id" : "ITEM-3", "itemData" : { "DOI" : "10.1002/mus.24271", "ISSN" : "1097-4598", "PMID" : "24828840", "abstract" : "Introduction: While current exercise guidelines recommend progressive, high-intensity resistance training (RT) to promote muscle hypertrophy and strength gains, controversy exists regarding the efficacy of lighter-load RT. We compared 2 work-matched RT interventions that differed in training intensity. Methods: Fifteen women underwent 10 weeks of unilateral knee extensor RT. One leg was trained at increasing intensity (intensity leg, InL, 50-80% 1-RM), and training progression in the contralateral leg (volume leg, VoL, 50% 1-RM) was based on increasing training volumes. Quadriceps muscle size (ultrasound, DXA) and strength (isokinetic dynamometry) were assessed on 4 occasions. Results: Both training programs induced significant, yet comparable increases in muscle size (InL: +4.6-12%, VoL: +3.1-11%) and strength (InL: +10-16%, VoL: +10-14%). Discussion: Training at lower than commonly suggested intensities may be an equally effective alternative form of RT. Factors other than training intensity, such as the total mechanical work during training, may strongly affect the training response. \u00a9 2014 Wiley Periodicals, Inc.", "author" : [ { "dropping-particle" : "", "family" : "Alegre", "given" : "Luis M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Aguado", "given" : "Xavier", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Rojas-Mart\u00edn", "given" : "Diego", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Mart\u00edn-Garc\u00eda", "given" : "Mar\u00eda", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ara", "given" : "Ignacio", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Csapo", "given" : "Robert", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Muscle & nerve", "id" : "ITEM-3", "issue" : "1", "issued" : { "date-parts" : [ [ "2015" ] ] }, "page" : "92-101", "title" : "Load-controlled moderate and high-intensity resistance training programs provoke similar strength gains in young women.", "type" : "article-journal", "volume" : "51" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[61,71,73]", "plainTextFormattedCitation" : "[61,71,73]", "previouslyFormattedCitation" : "[61,71,73]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[61,71,73] and high loads (low reps) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-2", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] }, { "id" : "ITEM-3", "itemData" : { "DOI" : "10.1016/j.exger.2013.08.010", "ISSN" : "1873-6815", "PMID" : "23999311", "abstract" : "Muscle adaptations can be induced by high-resistance exercise. Despite being potentially more suitable for older adults, low-resistance exercise protocols have been less investigated. We compared the effects of high- and low-resistance training on muscle volume, muscle strength, and force-velocity characteristics. Fifty-six older adults were randomly assigned to 12 weeks of leg press and leg extension training at either HIGH (2\u00d710-15 repetitions at 80% of one repetition maximum (1RM)), LOW (1\u00d780-100 repetitions at 20% of 1RM), or LOW+ (1\u00d760 repetitions at 20% of 1RM, followed by 1\u00d710-20 repetitions at 40% of 1RM). All protocols ended with muscle failure. Leg press and leg extension of 1RM were measured at baseline and post intervention and before the first training session in weeks 5 and 9. At baseline and post intervention, muscle volume (MV) was measured by CT-scan. A Biodex dynamometer evaluated knee extensor static peak torque in different knee angles (PT(stat90\u00b0), PT(stat120\u00b0), PT(stat150\u00b0)), dynamic peak torque at different speeds (PT(dyn60\u00b0s)(-1), PT(dyn180\u00b0s)(-1), PT(dyn240\u00b0s)(-1)), and speed of movement at 20% (S20), 40% (S40), and 60% (S60) of PTstat90\u00b0. HIGH and LOW+ resulted in greater improvements in 1RM strength than LOW (p<0.05). These differences were already apparent after week 5. Similar gains were found between groups in MV, PT(stat), PT(dyn60\u00b0s)(-1), and PT(dyn180\u00b0s)(-1). No changes were reported in speed of movement. HIGH tended to improve PT(dyn240\u00b0s)(-1) more than LOW or LOW+ (p=0.064). In conclusion, high- and low-resistance exercises ending with muscle failure may be similarly effective for hypertrophy. High-resistance training led to a higher increase in 1RM strength than low-resistance training (20% of 1RM), but this difference disappeared when using a mixed low-resistance protocol in which the resistance was intensified within a single exercise set (40% of 1RM). Our findings support the need for more research on low-resistance programs in older age, in particular long-term training studies and studies focusing on residual effects after training cessation.", "author" : [ { "dropping-particle" : "", "family" : "Roie", "given" : "Evelien", "non-dropping-particle" : "Van", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Delecluse", "given" : "Christophe", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Coudyzer", "given" : "Walter", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Boonen", "given" : "Steven", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Bautmans", "given" : "Ivan", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Experimental gerontology", "id" : "ITEM-3", "issue" : "11", "issued" : { "date-parts" : [ [ "2013", "11" ] ] }, "page" : "1351-61", "publisher" : "Elsevier Inc.", "title" : "Strength training at high versus low external resistance in older adults: effects on muscle volume, muscle strength, and force-velocity characteristics.", "type" : "article-journal", "volume" : "48" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5,6,74]", "plainTextFormattedCitation" : "[5,6,74]", "previouslyFormattedCitation" : "[5,6,74]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5,6,74] to induce increases in maximal strength. Indeed the majority of our strength results support the concept that maximal strength increases can be achieved with the use of either low or high repetitions, so long as there is periodic practice of lifting heavier loads (i.e., more frequent 1RM testing), whereas the disparity in maximum bench press strength changes remain in agreement with literature supporting the use of low repetitions with a high load. Tanimoto and colleagues observed similar increases in knee extensor 1RM strength following 12 weeks of progressive RT in untrained, healthy young men ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00741.2005", "ISBN" : "8750-7587", "ISSN" : "8750-7587", "PMID" : "16339347", "abstract" : "We investigated the acute and long-term effects of low-intensity resistance exercise (knee extension) with slow movement and tonic force generation on muscular size and strength. This type of exercise was expected to enhance the intramuscular hypoxic environment that might be a factor for muscular hypertrophy. Twenty-four healthy young men without experience of regular exercise training were assigned into three groups (n = 8 for each) and performed the following resistance exercise regimens: low-intensity [ approximately 50% of one-repetition maximum (1RM)] with slow movement and tonic force generation (3 s for eccentric and concentric actions, 1-s pause, and no relaxing phase; LST); high-intensity ( approximately 80% 1RM) with normal speed (1 s for concentric and eccentric actions, 1 s for relaxing; HN); low-intensity with normal speed (same intensity as for LST and same speed as for HN; LN). In LST and HN, the mean repetition maximum was 8RM. In LN, both intensity and amount of work were matched with those for LST. Each exercise session consisting of three sets was performed three times a week for 12 wk. In LST and HN, exercise training caused significant (P < 0.05) increases in cross-sectional area determined with MRI and isometric strength (maximal voluntary contraction) of the knee extensors, whereas no significant changes were seen in LN. Electromyographic and near-infrared spectroscopic analyses showed that one bout of LST causes sustained muscular activity and the largest muscle deoxygenation among the three types of exercise. The results suggest that intramuscular oxygen environment is important for exercise-induced muscular hypertrophy.", "author" : [ { "dropping-particle" : "", "family" : "Tanimoto", "given" : "Michiya", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ishii", "given" : "Naokata", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of applied physiology (Bethesda, Md. : 1985)", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2006" ] ] }, "page" : "1150-1157", "title" : "Effects of low-intensity resistance exercise with slow movement and tonic force generation on muscular function in young men.", "type" : "article-journal", "volume" : "100" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[80]", "plainTextFormattedCitation" : "[80]", "previouslyFormattedCitation" : "[80]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[80], finding a 27% increase in strength in the high repetition group (performing ~50% of 1RM) and a 33% increase in strength in the low repetition group (~80% of 1RM) with no difference between groups ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00741.2005", "ISBN" : "8750-7587", "ISSN" : "8750-7587", "PMID" : "16339347", "abstract" : "We investigated the acute and long-term effects of low-intensity resistance exercise (knee extension) with slow movement and tonic force generation on muscular size and strength. This type of exercise was expected to enhance the intramuscular hypoxic environment that might be a factor for muscular hypertrophy. Twenty-four healthy young men without experience of regular exercise training were assigned into three groups (n = 8 for each) and performed the following resistance exercise regimens: low-intensity [ approximately 50% of one-repetition maximum (1RM)] with slow movement and tonic force generation (3 s for eccentric and concentric actions, 1-s pause, and no relaxing phase; LST); high-intensity ( approximately 80% 1RM) with normal speed (1 s for concentric and eccentric actions, 1 s for relaxing; HN); low-intensity with normal speed (same intensity as for LST and same speed as for HN; LN). In LST and HN, the mean repetition maximum was 8RM. In LN, both intensity and amount of work were matched with those for LST. Each exercise session consisting of three sets was performed three times a week for 12 wk. In LST and HN, exercise training caused significant (P < 0.05) increases in cross-sectional area determined with MRI and isometric strength (maximal voluntary contraction) of the knee extensors, whereas no significant changes were seen in LN. Electromyographic and near-infrared spectroscopic analyses showed that one bout of LST causes sustained muscular activity and the largest muscle deoxygenation among the three types of exercise. The results suggest that intramuscular oxygen environment is important for exercise-induced muscular hypertrophy.", "author" : [ { "dropping-particle" : "", "family" : "Tanimoto", "given" : "Michiya", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ishii", "given" : "Naokata", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of applied physiology (Bethesda, Md. : 1985)", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2006" ] ] }, "page" : "1150-1157", "title" : "Effects of low-intensity resistance exercise with slow movement and tonic force generation on muscular function in young men.", "type" : "article-journal", "volume" : "100" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[80]", "plainTextFormattedCitation" : "[80]", "previouslyFormattedCitation" : "[80]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[80]. In contrast, Mitchell et al. ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6], evaluated knee extensor strength changes in a similar population of healthy, untrained young men performing either 30% (high repetition) or 80% (low repetition) of their 1RM to failure and found that following 10 weeks of RT 3-times per week, that both groups significantly increased knee extensor 1RM, however, the low repetition group had a greater increase in strength (33%) compared to the high repetition group (20%) ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1152/japplphysiol.00307.2012 japplphysiol.00307.2012 [pii]", "ISBN" : "1522-1601 (Electronic) 0161-7567 (Linking)", "ISSN" : "1522-1601", "PMID" : "22518835", "abstract" : "We have reported that the acute postexercise increases in muscle protein synthesis rates, with differing nutritional support, are predictive of longer-term training-induced muscle hypertrophy. Here, we aimed to test whether the same was true with acute exercise-mediated changes in muscle protein synthesis. Eighteen men (21 +/- 1 yr, 22.6 +/- 2.1 kg/m(2); means +/- SE) had their legs randomly assigned to two of three training conditions that differed in contraction intensity [% of maximal strength (1 repetition maximum)] or contraction volume (1 or 3 sets of repetitions): 30%-3, 80%-1, and 80%-3. Subjects trained each leg with their assigned regime for a period of 10 wk, 3 times/wk. We made pre- and posttraining measures of strength, muscle volume by magnetic resonance (MR) scans, as well as pre- and posttraining biopsies of the vastus lateralis, and a single postexercise (1 h) biopsy following the first bout of exercise, to measure signaling proteins. Training-induced increases in MR-measured muscle volume were significant (P < 0.01), with no difference between groups: 30%-3 = 6.8 +/- 1.8%, 80%-1 = 3.2 +/- 0.8%, and 80%-3= 7.2 +/- 1.9%, P = 0.18. Isotonic maximal strength gains were not different between 80%-1 and 80%-3, but were greater than 30%-3 (P = 0.04), whereas training-induced isometric strength gains were significant but not different between conditions (P = 0.92). Biopsies taken 1 h following the initial resistance exercise bout showed increased phosphorylation (P < 0.05) of p70S6K only in the 80%-1 and 80%-3 conditions. There was no correlation between phosphorylation of any signaling protein and hypertrophy. In accordance with our previous acute measurements of muscle protein synthetic rates a lower load lifted to failure resulted in similar hypertrophy as a heavy load lifted to failure.", "author" : [ { "dropping-particle" : "", "family" : "Mitchell", "given" : "Cameron J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Churchward-Venne", "given" : "Tyler a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "West", "given" : "Daniel W D", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burd", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Breen", "given" : "Leigh", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Baker", "given" : "Steven K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Phillips", "given" : "Stuart M", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "J Appl Physiol", "edition" : "2012/04/21", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012", "7" ] ] }, "language" : "eng", "note" : "From Duplicate 1 ( ", "page" : "71-77", "title" : "Resistance exercise load does not determine training-mediated hypertrophic gains in young men", "type" : "article-journal", "volume" : "113" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[6]", "plainTextFormattedCitation" : "[6]", "previouslyFormattedCitation" : "[6]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[6]. The observation that the group performing high repetitions in this study experienced similar increases in strength in the majority of the selected strength tests adds to the idea that high repetition exercise is as effective as low repetition RT at inducing significant strength adaptations when exercise is performed to volitional fatigue. We chose to test our participants’ maximal (1RM) strength every three weeks during the 12wk training study. We did so to minimize the possibility that the measured strength gains would not be affected by training specificity ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1007/s00421-002-0681-6", "ISSN" : "1439-6319", "PMID" : "12436270", "abstract" : "Thirty-two untrained men [mean (SD) age 22.5 (5.8) years, height 178.3 (7.2) cm, body mass 77.8 (11.9) kg] participated in an 8-week progressive resistance-training program to investigate the \"strength-endurance continuum\". Subjects were divided into four groups: a low repetition group (Low Rep, n = 9) performing 3-5 repetitions maximum (RM) for four sets of each exercise with 3 min rest between sets and exercises, an intermediate repetition group (Int Rep, n = 11) performing 9-11 RM for three sets with 2 min rest, a high repetition group (High Rep, n = 7) performing 20-28 RM for two sets with 1 min rest, and a non-exercising control group (Con, n = 5). Three exercises (leg press, squat, and knee extension) were performed 2 days/week for the first 4 weeks and 3 days/week for the final 4 weeks. Maximal strength [one repetition maximum, 1RM), local muscular endurance (maximal number of repetitions performed with 60% of 1RM), and various cardiorespiratory parameters (e.g., maximum oxygen consumption, pulmonary ventilation, maximal aerobic power, time to exhaustion) were assessed at the beginning and end of the study. In addition, pre- and post-training muscle biopsy samples were analyzed for fiber-type composition, cross-sectional area, myosin heavy chain (MHC) content, and capillarization. Maximal strength improved significantly more for the Low Rep group compared to the other training groups, and the maximal number of repetitions at 60% 1RM improved the most for the High Rep group. In addition, maximal aerobic power and time to exhaustion significantly increased at the end of the study for only the High Rep group. All three major fiber types (types I, IIA, and IIB) hypertrophied for the Low Rep and Int Rep groups, whereas no significant increases were demonstrated for either the High Rep or Con groups. However, the percentage of type IIB fibers decreased, with a concomitant increase in IIAB fibers for all three resistance-trained groups. These fiber-type conversions were supported by a significant decrease in MHCIIb accompanied by a significant increase in MHCIIa. No significant changes in fiber-type composition were found in the control samples. Although all three training regimens resulted in similar fiber-type transformations (IIB to IIA), the low to intermediate repetition resistance-training programs induced a greater hypertrophic effect compared to the high repetition regimen. The High Rep group, however, appeared better adapted for submaximal, pro\u2026", "author" : [ { "dropping-particle" : "", "family" : "Campos", "given" : "Gerson E R", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Luecke", "given" : "Thomas J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wendeln", "given" : "Heather K", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Toma", "given" : "Kumika", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hagerman", "given" : "Fredrick C", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Murray", "given" : "Thomas F", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ragg", "given" : "Kerry E", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Staron", "given" : "Robert S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "European journal of applied physiology", "id" : "ITEM-1", "issue" : "1-2", "issued" : { "date-parts" : [ [ "2002", "11" ] ] }, "page" : "50-60", "title" : "Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones.", "type" : "article-journal", "volume" : "88" }, "uris" : [ "" ] }, { "id" : "ITEM-2", "itemData" : { "DOI" : "10.1249/01.MSS.0000121945.36635.61", "ISBN" : "0195-9131 (Print)\\r0195-9131 (Linking)", "ISSN" : "01959131", "PMID" : "15064596", "abstract" : "Progression in resistance training is a dynamic process that requires an exercise prescription process, evaluation of training progress, and careful development of target goals. The process starts with the determination of individual needs and training goals. This involves decisions regarding questions as to what muscles must be trained, injury prevention sites, metabolic demands of target training goals, etc. The single workout must then be designed reflecting these targeted program goals including the choice of exercises, order of exercise, amount of rest used between sets and exercises, number of repetitions and sets used for each exercise, and the intensity of each exercise. For progression, these variables must then be varied over time and the exercise prescription altered to maintain or advance specific training goals and to avoid overtraining. A careful system of goal targeting, exercise testing, proper exercise technique, supervision, and optimal exercise prescription all contribute to the successful implementation of a resistance training program.", "author" : [ { "dropping-particle" : "", "family" : "Kraemer", "given" : "William J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ratamess", "given" : "Nicholas a.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and Science in Sports and Exercise", "id" : "ITEM-2", "issue" : "4", "issued" : { "date-parts" : [ [ "2004" ] ] }, "page" : "674-688", "title" : "Fundamentals of Resistance Training: Progression and Exercise Prescription", "type" : "article-journal", "volume" : "36" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[5,78]", "plainTextFormattedCitation" : "[5,78]", "previouslyFormattedCitation" : "[5,78]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[5,78]. Specially, in the LR group, who were lifting weights at between 70-80% of their 1RM this load is only 20-30% less than their 1RM while in contrast the HR group lifting weight at ~40-50% of 1RM would be 60-50% less than their 1RM. Thus, the principle of specificity would dictate that the LR group would be much more ‘practiced’ at lifting closer to a 1RM load than the HR group as the LR group would have a greater positive transfer of learning by the motor system resulting in an increase in neural coordination ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.2165/00007256-200131120-00001", "ISSN" : "0112-1642", "PMID" : "11665911", "abstract" : "It has long been believed that resistance training is accompanied by changes within the nervous system that play an important role in the development of strength. Many elements of the nervous system exhibit the potential for adaptation in response to resistance training, including supraspinal centres, descending neural tracts, spinal circuitry and the motor end plate connections between motoneurons and muscle fibres. Yet the specific sites of adaptation along the neuraxis have seldom been identified experimentally, and much of the evidence for neural adaptations following resistance training remains indirect. As a consequence of this current lack of knowledge, there exists uncertainty regarding the manner in which resistance training impacts upon the control and execution of functional movements. We aim to demonstrate that resistance training is likely to cause adaptations to many neural elements that are involved in the control of movement, and is therefore likely to affect movement execution during a wide range of tasks. We review a small number of experiments that provide evidence that resistance training affects the way in which muscles that have been engaged during training are recruited during related movement tasks. The concepts addressed in this article represent an important new approach to research on the effects of resistance training. They are also of considerable practical importance, since most individuals perform resistance training in the expectation that it will enhance their performance in related functional tasks.", "author" : [ { "dropping-particle" : "", "family" : "Carroll", "given" : "T J", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Riek", "given" : "S", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Carson", "given" : "R G", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Sports medicine (Auckland, N.Z.)", "id" : "ITEM-1", "issue" : "12", "issued" : { "date-parts" : [ [ "2001" ] ] }, "page" : "829-840", "title" : "Neural adaptations to resistance training: implications for movement control.", "type" : "article-journal", "volume" : "31" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[81]", "plainTextFormattedCitation" : "[81]", "previouslyFormattedCitation" : "[81]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[81]. Thus, simply measuring 1RM pre- and post-intervention would bias the results toward a result for greater strength gains that would favour the LR group due to learning/practice. In fact we observed equivalent gains in strength in all of 1RM results between groups with the exception of bench press. We speculate that the disparity in the increase in maximal bench press strength between our intervention groups could be caused by a lesser capacity for neural adaptation as compared to the other exercises given that bench press was included in all of our subjects’ habitual training regimes and thus is more familiar to those who perform RT regularly and may have already reached a plateau ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "author" : [ { "dropping-particle" : "", "family" : "Richmond", "given" : "Scott R.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Godard", "given" : "Michael P", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Strength and Conditioning Research", "id" : "ITEM-1", "issue" : "4", "issued" : { "date-parts" : [ [ "2004" ] ] }, "page" : "846-849", "title" : "The Effects of Varied Rest Periods Between Sets to Failure Using the Bench Press in Recreationally Trained Men", "type" : "article-journal", "volume" : "18" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[82]", "plainTextFormattedCitation" : "[82]", "previouslyFormattedCitation" : "[82]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[82]. This is in comparison to the other strength measures examined in the current study such as leg press, leg extension, and shoulder press which were less frequently reported as being included in the RT program of these previously trained individuals (less than 5% of participants regularly used machine based leg exercises and less than 8% used a machine based shoulder exercise). These exercises were chosen both for comparison to existing literature, as well as to reduce the risk of injuries resulting from the use of free weights which have a higher degree of instability, especially with higher repetitions and with volitional fatigue. Therefore it is possible that despite training status, if the capacity exists for significant neural adaptation, high and low repetition resistance exercise are likely equivalent in their ability to stimulate muscle hypertrophy and strength gains. However when the exercise is well-practiced, high-load, low-repetition programs are more beneficial at inducing increases in maximum strength.2.4.3LimitationsTo our knowledge, this study is only the second to examine the effects of high and low repetition RT in previously resistance trained young men. Unique to this study, is the inclusion of a large sample size (n=49 total: 24 vs. 25 participants) to ensure validity of the comparisons which is in contrast to the smaller sample size (n=16: 8 vs. 8) used previously ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1519/JSC.0000000000000958", "ISBN" : "0000000000000", "ISSN" : "1064-8011", "author" : [ { "dropping-particle" : "", "family" : "Schoenfeld", "given" : "Brad J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Peterson", "given" : "Mark D.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Ogborn", "given" : "Dan", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Contreras", "given" : "Bret", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Sonmez", "given" : "Gul T.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of Strength and Conditioning Research", "id" : "ITEM-1", "issued" : { "date-parts" : [ [ "2015" ] ] }, "number-of-pages" : "1", "title" : "Effects of Low- Versus High-Load Resistance Training on Muscle Strength and Hypertrophy in Well-Trained Men", "type" : "book" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[83]", "plainTextFormattedCitation" : "[83]", "previouslyFormattedCitation" : "[83]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[83]. Nonetheless, there are still inherent limitations within our study design. The use of DXA (in our laboratory an iDXA) was used in place of MRI, which is the gold standard technique for determination of muscle hypertrophy. The iDXA gives an excellent measure of whole body fat- and bone-free (i.e., lean) mass; however the error of iDXA has been shown to be approximately 1.5% and this variability is greater when estimating body segments ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1249/MSS.0b013e318228b60e", "ISSN" : "01959131", "PMID" : "22179140", "abstract" : "PURPOSE: Dual-energy x-ray absorptiometry (DXA) is becoming a popular tool to measure body composition in athletes, owing to its ease of operation and comprehensive analysis of body composition. This study represents the first systematic investigation of the reliability of DXA measurements of body composition in trained individuals and includes measurements of daily variability as well as the specific effect of the intake of a meal.\\n\\nMETHODS: Physically active young adults (15 females, 16 males) underwent five whole-body DXA scans during a 2-d period: in the morning after an overnight fast, ~5 min later after repositioning on the scanning bed, ~8 h later after usual daily activities, and the next morning before and ~30 min after consumption of a simple breakfast. Magnitudes of typical (standard) errors of measurement and changes in the mean of DXA measures were assessed by standardization.\\n\\nRESULTS: Repositioning produced trivial typical errors for whole-body composition, whereas regional body composition showed substantial errors. Daily activities and consumption of breakfast generally produced a substantial increase in the typical error and mean of DXA estimates of total and regional lean mass and associated body mass.\\n\\nCONCLUSIONS: Having a standardized scanning protocol and fasted subjects is the most practical way to minimize measurement errors. Future studies involving DXA in measuring body composition should report their scanning and analysis protocol with their associated typical errors of measurement so that the level of reliability can be assessed.", "author" : [ { "dropping-particle" : "", "family" : "Nana", "given" : "Alisa", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Slater", "given" : "Gary J.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Hopkins", "given" : "Will G.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Burke", "given" : "Louise M.", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Medicine and Science in Sports and Exercise", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2012" ] ] }, "page" : "180-189", "title" : "Effects of daily activities on dual-energy X-ray absorptiometry measurements of body composition in active people", "type" : "article-journal", "volume" : "44" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[84]", "plainTextFormattedCitation" : "[84]", "previouslyFormattedCitation" : "[84]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[84]. One of the major limitations of iDXA is the variability in lean mass estimation as changes in soft tissue hydration status can result in inconsistent measures. Despite the limitations, the iDXA is still much improved from previous models of dual-energy x-ray absorptiometry ADDIN CSL_CITATION { "citationItems" : [ { "id" : "ITEM-1", "itemData" : { "DOI" : "10.1016/j.jocd.2008.09.004.iDXA", "author" : [ { "dropping-particle" : "", "family" : "Hull", "given" : "Holly", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "He", "given" : "Qing", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Thornton", "given" : "John", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Javed", "given" : "Fahad", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Wang", "given" : "Jack", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Pierson", "given" : "Richard N", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" }, { "dropping-particle" : "", "family" : "Gallagher", "given" : "Dympna", "non-dropping-particle" : "", "parse-names" : false, "suffix" : "" } ], "container-title" : "Journal of clinical Densitometry", "id" : "ITEM-1", "issue" : "1", "issued" : { "date-parts" : [ [ "2009" ] ] }, "page" : "95-102", "title" : "iDXA, Prodigy, and DPXL dual-energy X-ray absorptiometry whole-body scans: a cross-calibration study", "type" : "article-journal", "volume" : "12" }, "uris" : [ "" ] } ], "mendeley" : { "formattedCitation" : "[85]", "plainTextFormattedCitation" : "[85]", "previouslyFormattedCitation" : "[85]" }, "properties" : { "noteIndex" : 0 }, "schema" : "" }[85]. I propose that our day-to-day calibration of the iDXA using the whole-body 3-compartment phantom allowed us to have greater internal validity than previous work.2.4.4ConclusionsIn conclusion, these data show that a low-load, high-repetition resistance training regime can induce significant increases in muscle hypertrophy and strength that are comparable to those found with a high-load, low-repetition training regime as long as the load is lifted until volitional fatigue. It was found that increases in LBM occurred in both LR and HR groups with no differences between groups. We also found a significant increase in 1RM strength for the leg press, leg extension and shoulder press exercises again with no differences between groups. While 1RM bench press increased in both groups, it increased to a greater extent in the LR group. We speculate that the increases in muscle strength and hypertrophy seen in our previously resistance trained participants in the HR group was due to them performing a greater volume of exercise and lifting to volitional failure. 2.4.5Future DirectionsThe present study aimed to compare the effectiveness of a high and low repetition chronic resistance exercise training protocol on strength and muscle hypertrophy in previously trained men. It would be of practical interest to examine changes in hypertrophy and strength as well as perceived exertion and pain in populations where heavy loaded resistance exercise may not be feasible, safe, or enjoyable to participants such as with elderly populations or in individuals with inflammatory conditions, such as osteoarthritis. Finally, the molecular mechanisms that govern skeletal muscle plasticity in response to resistance exercise remain largely unknown. Future work using a range of biochemical and molecular techniques are now needed in order to elucidate how the mechanical signal from RE is transmitted and leads to the biochemical events that lead to an upregulation of the translational machinery and, ultimately, hypertrophy in humans. REFERENCESADDIN Mendeley Bibliography CSL_BIBLIOGRAPHY 1. Lee RC, Wang Z, Heo M, Ross R, Jannsen I, Heymsfield SB. Total-body skeletal muscle mass: Development and cross-validation of anthropometric prediction models. Am J Clin Nutr. 2000;72: 796–803. 2. Richter E a, Hargreaves M. Exercise, GLUT4, and skeletal muscle glucose uptake. Physiol Rev. 2013;93: 993–1017. doi:10.1152/physrev.00038.20123. Wolfe RR. The underappreciated role of muscle in health and disease. Am J Clin Nutr. 2006;84: 475–82. Available: . Egan B, Zierath JR. Exercise metabolism and the molecular regulation of skeletal muscle adaptation. Cell Metab. Elsevier Inc.; 2013;17: 162–184. doi:10.1016/j.cmet.2012.12.0125. 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