Peripheral Quantitative Computerized Tomography (pQCT) is ...



Center for Human Phenomic Science: Nutrition Core LaboratoryThe?Nutrition Core Laboratory is housed in the Nutrition and Growth Laboratory, a state-of-the-art facility for the assessment of growth, body dimensions, body composition (the amount of muscle, fat, and bone in the body), bone density, and muscle strength and energy expenditure. The Lab provides consultation and technical expertise for these assessments. The?Unit has two locations with experienced research technicians for performing nutrition assessments. Babette Zemel, Ph.D. serves as the Core Director.Procedural Costs: Costs associated with these procedures are based on estimated supply and operating cost, and staff time needed for scheduling, performing the examination, processing, and analyzing the results, delivery of results to the investigator. ANTHROPOMETRIC ASSESSMENT OF GROWTH, BODY DIMENSIONS, AND BODY COMPOSITION: The Nutrition Core Laboratory has the capability of performing a wide array of anthropometric measurements of infants, children, and adults to assess growth, body dimensions, and body composition. The equipment available for anthropometric examinations includes: infant (0.01kg), adult (0.1kg) and wheel chair (0.1kg) accessible Scaletronix digital scales (Scaletronix, Skaneateles, NY), Harpenden (Crymych, UK) neonatometers and infantometers for measurement of length and stadiometers for measurement of stature (0.1 cm), retractable tape measures (0.1 cm) for measuring circumferences (head, arm, waist, hip, etc.), Holtain (Crymych, UK) skinfold thickness calipers (0.1mm) to assess regional subcutaneous fat stores (e.g., biceps, triceps, subscapular, suprailiac skinfold thicknesses) and/or body composition (fat mass, fat-free mass, and percent body fat), and a variety of sliding calipers (0.1 cm) and anthropometers (0.1 cm) to measure body breadths (e.g., elbow breadth, biacromial diameters) and limb lengths (forearm, lower leg) as indicators of body proportions or alternative measures of linear growth. Abdometers are available for the measurement of sagittal abdominal diameter, an anthropometric correlate of intraabdominal fat (Holtain Kahn Abdominal Caliper, Holtain, Crymych, UK). In addition, the Nutrition Core Laboratory has several high precision knee height measuring devices which measures the length of the lower leg from the heel to the superior surface of the knee for the assessment of short-term growth of the lower leg (0.01 mm) ADDIN EN.CITE <EndNote><Cite><Author>Cronk</Author><Year>1989</Year><RecNum>3240</RecNum><DisplayText><style face="superscript">1</style></DisplayText><record><rec-number>3240</rec-number><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Cronk, CE </author><author>Stallings, VA</author><author>Spender, QW</author><author>Ross, JL</author><author>Widdoes, HD</author></authors></contributors><titles><title>Measurement of short term linear growth with a new knee height measuring device</title><secondary-title>Am J Human Biol</secondary-title></titles><periodical><full-title>Am J Human Biol</full-title></periodical><pages>421-428</pages><volume>1</volume><dates><year>1989</year></dates><urls></urls></record></Cite></EndNote>1. Assessment of sexual maturation is often included in the anthropometric examination. The Nutrition Core Laboratory provides a self-assessment questionnaire originally designed by Morris and Udry ADDIN EN.CITE <EndNote><Cite><Author>Morris</Author><Year>1980</Year><RecNum>2442</RecNum><DisplayText><style face="superscript">2</style></DisplayText><record><rec-number>2442</rec-number><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Morris, N.M.</author><author>Udry, J.R.</author></authors></contributors><titles><title>Validation of a self-administered instrument to assess stage of adolescent development</title><secondary-title>J Youth and Adolesc</secondary-title></titles><periodical><full-title>J Youth and Adolesc</full-title></periodical><pages>271-280</pages><volume>9</volume><dates><year>1980</year></dates><urls></urls></record></Cite></EndNote>2 that uses pictograms and descriptions for breast stage in girls, genital stage in boys, and pubic hair development in both boys and girls based on the sexual maturity stages defined by Tanner ADDIN EN.CITE <EndNote><Cite><Author>Tanner</Author><Year>1962</Year><RecNum>321</RecNum><DisplayText><style face="superscript">3</style></DisplayText><record><rec-number>321</rec-number><ref-type name="Book">6</ref-type><contributors><authors><author>Tanner, J. M.</author></authors></contributors><titles><title>Growth at Adolescence</title></titles><edition>2nd</edition><dates><year>1962</year></dates><pub-location>Oxford</pub-location><publisher>Blackwell Scientific Publication</publisher><urls></urls></record></Cite></EndNote>3. The questionnaire is explained to the study participant (with or without a parent present) in advance, and then they are left to complete the questionnaire in private. The anthropometric exam room is equipped with a full-length mirror to aid in the self-assessment process.The Nutrition Core Laboratory has highly trained research anthropometrists. Most measurements are obtained in triplicate to provide a robust measurement, and to monitor precision and intra-observer reliability. Anthropometric examination protocols are modified to meet the needs of the investigator and the study population. Dr. Zemel, Director of the Nutrition Core Laboratory, is available for consultation on the selection of measures, study design, computations of derived measures, and selection of reference data for interpretation.BODY COMPOSITION: The Nutrition Core Laboratory has several methods available for body composition assessment. Pea Pod Air Displacement Plethysmography (COSMED, Concord, CA) is a safe, noninvasive, reliable, accurate and brief (approximately 7 minutes) test for infants to estimate fat mass, fat-free mass and percent body fat using menu driven softwarePEVuZE5vdGU+PENpdGU+PEF1dGhvcj5FbGxpczwvQXV0aG9yPjxZZWFyPjIwMDc8L1llYXI+PFJl

Y051bT4zMzcyPC9SZWNOdW0+PERpc3BsYXlUZXh0PjxzdHlsZSBmYWNlPSJzdXBlcnNjcmlwdCI+

NDwvc3R5bGU+PC9EaXNwbGF5VGV4dD48cmVjb3JkPjxyZWMtbnVtYmVyPjMzNzI8L3JlYy1udW1i

ZXI+PHJlZi10eXBlIG5hbWU9IkpvdXJuYWwgQXJ0aWNsZSI+MTc8L3JlZi10eXBlPjxjb250cmli

dXRvcnM+PGF1dGhvcnM+PGF1dGhvcj5FbGxpcywgSy4gSi48L2F1dGhvcj48YXV0aG9yPllhbywg

TS48L2F1dGhvcj48YXV0aG9yPlNoeXBhaWxvLCBSLiBKLjwvYXV0aG9yPjxhdXRob3I+VXJsYW5k

bywgQS48L2F1dGhvcj48YXV0aG9yPldvbmcsIFcuIFcuPC9hdXRob3I+PGF1dGhvcj5IZWlyZCwg

Vy4gQy48L2F1dGhvcj48L2F1dGhvcnM+PC9jb250cmlidXRvcnM+PGF1dGgtYWRkcmVzcz5VU0RB

LUFSUyBDaGlsZHJlbiZhcG9zO3MgTnV0cml0aW9uIFJlc2VhcmNoIENlbnRlciwgRGVwYXJ0bWVu

dCBvZiBQZWRpYXRyaWNzLCBCYXlsb3IgQ29sbGVnZSBvZiBNZWRpY2luZSwgSG91c3RvbiwgVGV4

YXMgNzcwMzAsIFVTQS4ga2VsbGlzQGJjbS50bWMuZWR1PC9hdXRoLWFkZHJlc3M+PHRpdGxlcz48

dGl0bGU+Qm9keS1jb21wb3NpdGlvbiBhc3Nlc3NtZW50IGluIGluZmFuY3k6IGFpci1kaXNwbGFj

ZW1lbnQgcGxldGh5c21vZ3JhcGh5IGNvbXBhcmVkIHdpdGggYSByZWZlcmVuY2UgNC1jb21wYXJ0

bWVudCBtb2RlbDwvdGl0bGU+PHNlY29uZGFyeS10aXRsZT5BbSBKIENsaW4gTnV0cjwvc2Vjb25k

YXJ5LXRpdGxlPjwvdGl0bGVzPjxwZXJpb2RpY2FsPjxmdWxsLXRpdGxlPkFtZXJpY2FuIEpvdXJu

YWwgb2YgQ2xpbmljYWwgTnV0cml0aW9uPC9mdWxsLXRpdGxlPjxhYmJyLTE+QW0uIEouIENsaW4u

IE51dHIuPC9hYmJyLTE+PGFiYnItMj5BbSBKIENsaW4gTnV0cjwvYWJici0yPjwvcGVyaW9kaWNh

bD48cGFnZXM+OTAtNTwvcGFnZXM+PHZvbHVtZT44NTwvdm9sdW1lPjxudW1iZXI+MTwvbnVtYmVy

PjxrZXl3b3Jkcz48a2V5d29yZD5BYnNvcnB0aW9tZXRyeSwgUGhvdG9uL21ldGhvZHM8L2tleXdv

cmQ+PGtleXdvcmQ+QWRpcG9zZSBUaXNzdWUvKm1ldGFib2xpc208L2tleXdvcmQ+PGtleXdvcmQ+

KkJvZHkgQ29tcG9zaXRpb248L2tleXdvcmQ+PGtleXdvcmQ+Qm9keSBXYXRlci9tZXRhYm9saXNt

L3BoeXNpb2xvZ3k8L2tleXdvcmQ+PGtleXdvcmQ+Qm9uZSBhbmQgQm9uZXMvbWV0YWJvbGlzbTwv

a2V5d29yZD48a2V5d29yZD5GZW1hbGU8L2tleXdvcmQ+PGtleXdvcmQ+SHVtYW5zPC9rZXl3b3Jk

PjxrZXl3b3JkPkluZmFudDwva2V5d29yZD48a2V5d29yZD5JbmZhbnQgTnV0cml0aW9uYWwgUGh5

c2lvbG9naWNhbCBQaGVub21lbmE8L2tleXdvcmQ+PGtleXdvcmQ+SW5mYW50LCBOZXdib3JuLypn

cm93dGggJmFtcDsgZGV2ZWxvcG1lbnQvbWV0YWJvbGlzbTwva2V5d29yZD48a2V5d29yZD5NYWxl

PC9rZXl3b3JkPjxrZXl3b3JkPipNb2RlbHMsIEJpb2xvZ2ljYWw8L2tleXdvcmQ+PGtleXdvcmQ+

UGxldGh5c21vZ3JhcGh5LyptZXRob2RzPC9rZXl3b3JkPjxrZXl3b3JkPlBvdGFzc2l1bS9tZXRh

Ym9saXNtPC9rZXl3b3JkPjxrZXl3b3JkPlJlZmVyZW5jZSBWYWx1ZXM8L2tleXdvcmQ+PGtleXdv

cmQ+UmVwcm9kdWNpYmlsaXR5IG9mIFJlc3VsdHM8L2tleXdvcmQ+PGtleXdvcmQ+U2Vuc2l0aXZp

dHkgYW5kIFNwZWNpZmljaXR5PC9rZXl3b3JkPjwva2V5d29yZHM+PGRhdGVzPjx5ZWFyPjIwMDc8

L3llYXI+PHB1Yi1kYXRlcz48ZGF0ZT5KYW48L2RhdGU+PC9wdWItZGF0ZXM+PC9kYXRlcz48YWNj

ZXNzaW9uLW51bT4xNzIwOTE4MjwvYWNjZXNzaW9uLW51bT48dXJscz48cmVsYXRlZC11cmxzPjx1

cmw+aHR0cDovL3d3dy5uY2JpLm5sbS5uaWguZ292L2VudHJlei9xdWVyeS5mY2dpP2NtZD1SZXRy

aWV2ZSZhbXA7ZGI9UHViTWVkJmFtcDtkb3B0PUNpdGF0aW9uJmFtcDtsaXN0X3VpZHM9MTcyMDkx

ODIgPC91cmw+PC9yZWxhdGVkLXVybHM+PC91cmxzPjwvcmVjb3JkPjwvQ2l0ZT48L0VuZE5vdGU+

ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5FbGxpczwvQXV0aG9yPjxZZWFyPjIwMDc8L1llYXI+PFJl

Y051bT4zMzcyPC9SZWNOdW0+PERpc3BsYXlUZXh0PjxzdHlsZSBmYWNlPSJzdXBlcnNjcmlwdCI+

NDwvc3R5bGU+PC9EaXNwbGF5VGV4dD48cmVjb3JkPjxyZWMtbnVtYmVyPjMzNzI8L3JlYy1udW1i

ZXI+PHJlZi10eXBlIG5hbWU9IkpvdXJuYWwgQXJ0aWNsZSI+MTc8L3JlZi10eXBlPjxjb250cmli

dXRvcnM+PGF1dGhvcnM+PGF1dGhvcj5FbGxpcywgSy4gSi48L2F1dGhvcj48YXV0aG9yPllhbywg

TS48L2F1dGhvcj48YXV0aG9yPlNoeXBhaWxvLCBSLiBKLjwvYXV0aG9yPjxhdXRob3I+VXJsYW5k

bywgQS48L2F1dGhvcj48YXV0aG9yPldvbmcsIFcuIFcuPC9hdXRob3I+PGF1dGhvcj5IZWlyZCwg

Vy4gQy48L2F1dGhvcj48L2F1dGhvcnM+PC9jb250cmlidXRvcnM+PGF1dGgtYWRkcmVzcz5VU0RB

LUFSUyBDaGlsZHJlbiZhcG9zO3MgTnV0cml0aW9uIFJlc2VhcmNoIENlbnRlciwgRGVwYXJ0bWVu

dCBvZiBQZWRpYXRyaWNzLCBCYXlsb3IgQ29sbGVnZSBvZiBNZWRpY2luZSwgSG91c3RvbiwgVGV4

YXMgNzcwMzAsIFVTQS4ga2VsbGlzQGJjbS50bWMuZWR1PC9hdXRoLWFkZHJlc3M+PHRpdGxlcz48

dGl0bGU+Qm9keS1jb21wb3NpdGlvbiBhc3Nlc3NtZW50IGluIGluZmFuY3k6IGFpci1kaXNwbGFj

ZW1lbnQgcGxldGh5c21vZ3JhcGh5IGNvbXBhcmVkIHdpdGggYSByZWZlcmVuY2UgNC1jb21wYXJ0

bWVudCBtb2RlbDwvdGl0bGU+PHNlY29uZGFyeS10aXRsZT5BbSBKIENsaW4gTnV0cjwvc2Vjb25k

YXJ5LXRpdGxlPjwvdGl0bGVzPjxwZXJpb2RpY2FsPjxmdWxsLXRpdGxlPkFtZXJpY2FuIEpvdXJu

YWwgb2YgQ2xpbmljYWwgTnV0cml0aW9uPC9mdWxsLXRpdGxlPjxhYmJyLTE+QW0uIEouIENsaW4u

IE51dHIuPC9hYmJyLTE+PGFiYnItMj5BbSBKIENsaW4gTnV0cjwvYWJici0yPjwvcGVyaW9kaWNh

bD48cGFnZXM+OTAtNTwvcGFnZXM+PHZvbHVtZT44NTwvdm9sdW1lPjxudW1iZXI+MTwvbnVtYmVy

PjxrZXl3b3Jkcz48a2V5d29yZD5BYnNvcnB0aW9tZXRyeSwgUGhvdG9uL21ldGhvZHM8L2tleXdv

cmQ+PGtleXdvcmQ+QWRpcG9zZSBUaXNzdWUvKm1ldGFib2xpc208L2tleXdvcmQ+PGtleXdvcmQ+

KkJvZHkgQ29tcG9zaXRpb248L2tleXdvcmQ+PGtleXdvcmQ+Qm9keSBXYXRlci9tZXRhYm9saXNt

L3BoeXNpb2xvZ3k8L2tleXdvcmQ+PGtleXdvcmQ+Qm9uZSBhbmQgQm9uZXMvbWV0YWJvbGlzbTwv

a2V5d29yZD48a2V5d29yZD5GZW1hbGU8L2tleXdvcmQ+PGtleXdvcmQ+SHVtYW5zPC9rZXl3b3Jk

PjxrZXl3b3JkPkluZmFudDwva2V5d29yZD48a2V5d29yZD5JbmZhbnQgTnV0cml0aW9uYWwgUGh5

c2lvbG9naWNhbCBQaGVub21lbmE8L2tleXdvcmQ+PGtleXdvcmQ+SW5mYW50LCBOZXdib3JuLypn

cm93dGggJmFtcDsgZGV2ZWxvcG1lbnQvbWV0YWJvbGlzbTwva2V5d29yZD48a2V5d29yZD5NYWxl

PC9rZXl3b3JkPjxrZXl3b3JkPipNb2RlbHMsIEJpb2xvZ2ljYWw8L2tleXdvcmQ+PGtleXdvcmQ+

UGxldGh5c21vZ3JhcGh5LyptZXRob2RzPC9rZXl3b3JkPjxrZXl3b3JkPlBvdGFzc2l1bS9tZXRh

Ym9saXNtPC9rZXl3b3JkPjxrZXl3b3JkPlJlZmVyZW5jZSBWYWx1ZXM8L2tleXdvcmQ+PGtleXdv

cmQ+UmVwcm9kdWNpYmlsaXR5IG9mIFJlc3VsdHM8L2tleXdvcmQ+PGtleXdvcmQ+U2Vuc2l0aXZp

dHkgYW5kIFNwZWNpZmljaXR5PC9rZXl3b3JkPjwva2V5d29yZHM+PGRhdGVzPjx5ZWFyPjIwMDc8

L3llYXI+PHB1Yi1kYXRlcz48ZGF0ZT5KYW48L2RhdGU+PC9wdWItZGF0ZXM+PC9kYXRlcz48YWNj

ZXNzaW9uLW51bT4xNzIwOTE4MjwvYWNjZXNzaW9uLW51bT48dXJscz48cmVsYXRlZC11cmxzPjx1

cmw+aHR0cDovL3d3dy5uY2JpLm5sbS5uaWguZ292L2VudHJlei9xdWVyeS5mY2dpP2NtZD1SZXRy

aWV2ZSZhbXA7ZGI9UHViTWVkJmFtcDtkb3B0PUNpdGF0aW9uJmFtcDtsaXN0X3VpZHM9MTcyMDkx

ODIgPC91cmw+PC9yZWxhdGVkLXVybHM+PC91cmxzPjwvcmVjb3JkPjwvQ2l0ZT48L0VuZE5vdGU+

ADDIN EN.CITE.DATA 4. Body mass, volume, density, and surface area are also determined. Sedation is not required and it can accommodate infants weighing between 1 kg and 8 kg (17.6 lbs.). Multifrequency Bioelectrical Impedance Analyzers (BIA): the HYDRA- ECF/ICF BIA (Xitron Technologies, Inc., San Diego, CA) is available for body composition for children and adults. The Nutrition Core Laboratory has two BIA machines to obtain non-invasive, rapid measurements of total body water, fat-free mass, fat mass, percent body fat of the total body and body segments based on resistance and reactance measurements. The device is small and portable. Other body composition techniques include whole body DXA scans and anthropometric assessment. These are described in other sections.Highly skilled research technicians are available for performing these body composition tests.BONE HEALTH ASSESSMENT:The Nutrition Core Laboratory offers three techniques for bone health assessment. Each technique is available at both Nutrition Core Laboratory locations.Dual Energy X-ray Absorptiometry (DXA) is the technique most commonly used in the clinical diagnosis of osteoporosis in adults and low bone mass in children. Bone mineral content (BMC) and areal-bone mineral density (aBMD) of the anterior-posterior spine, lateral spine, proximal femur, left forearm, and whole body can be assessed by DXA. The CHPS Nutrition Core is equipped with two DXA devices: the satellite CHPS facility at 3550 Market Street has a Hologic DiscoveryA bone densitometer (Hologic, Bedford, MA) operating in software version 13.4; and the main facility at the Children’s Hospital of Philadelphia has a HorizonA bone densitometer (Hologic, Bedford, MA) operating in software version 5.3. Each scan generates a measure of bone area, BMC, and areal-BMD. DXA is also used for body composition assessment. The whole body scan also provides regional and total body estimates of fat mass, fat-free mass, lean body mass and percent body fat. All scans are obtained following standardized procedures as recommended by the manufacturer. It takes approximately 20 minutes to complete all DXA measurements. Instant Vertebral Assessment (IVA) for determination of spine deformities is also available. The technique uses very low-dose x-ray exposures. The effective radiation dose for adults from DXA scans of the lumbar spine, hip and whole body are each about 10 μSv, and the forearm scan is less than 1 μSV. ADDIN EN.CITE <EndNote><Cite><Author>International Atomic Energy Agency</Author><Year>2010</Year><RecNum>371</RecNum><DisplayText><style face="superscript">5</style></DisplayText><record><rec-number>371</rec-number><foreign-keys><key app="EN" db-id="vezset9paxw926ev2z0vse5bfdzr2pzvdxap" timestamp="1484172864">371</key></foreign-keys><ref-type name="Electronic Article">43</ref-type><contributors><authors><author>International Atomic Energy Agency,</author></authors></contributors><titles><title>Dual energy x ray absorptiometry for bone mineral density and body composition assessment.</title><secondary-title>IAEA Human Health Series no. 15</secondary-title></titles><periodical><full-title>IAEA Human Health Series no. 15</full-title></periodical><dates><year>2010</year><pub-dates><date>11Jan2017</date></pub-dates></dates><pub-location>Vienna</pub-location><urls><related-urls><url> For a 10-year-old: spine scan 2.7 ?Sv, total body 2.7 ?Sv, forearm 0.07 ?Sv and proximal femur 8.3 ?Sv, totaling 13.8 ?Sv). ADDIN EN.CITE <EndNote><Cite><Author>Thomas</Author><Year>2005</Year><RecNum>199</RecNum><DisplayText><style face="superscript">6</style></DisplayText><record><rec-number>199</rec-number><foreign-keys><key app="EN" db-id="ft0rrwfz4xz0d1e0p9v50x09vawaa2df55sf" timestamp="1469095623">199</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Thomas, S. R.</author><author>Kalkwarf, H. J.</author><author>Buckley, D. D.</author><author>Heubi, J. E.</author></authors></contributors><auth-address>Department of Radiology, University of Cincinnati, College of Medicine, Cincinnati, OH, USA. steve.thomas@uc.edu</auth-address><titles><title>Effective dose of dual-energy X-ray absorptiometry scans in children as a function of age</title><secondary-title>J Clin Densitom</secondary-title></titles><periodical><full-title>J Clin Densitom</full-title></periodical><pages>415-22</pages><volume>8</volume><number>4</number><keywords><keyword>Absorptiometry, Photon/instrumentation</keyword><keyword>Adolescent</keyword><keyword>Adult</keyword><keyword>Age Factors</keyword><keyword>Bone Density/*physiology</keyword><keyword>Child</keyword><keyword>Child, Preschool</keyword><keyword>Female</keyword><keyword>Forearm/*radiography</keyword><keyword>Hip/*radiography</keyword><keyword>Humans</keyword><keyword>Infant</keyword><keyword>Lumbar Vertebrae/*radiography</keyword><keyword>Male</keyword><keyword>Phantoms, Imaging</keyword><keyword>Radiation Dosage</keyword><keyword>Reproducibility of Results</keyword></keywords><dates><year>2005</year><pub-dates><date>Winter</date></pub-dates></dates><isbn>1094-6950 (Print)&#xD;1094-6950 (Linking)</isbn><accession-num>16311426</accession-num><urls><related-urls><url> This radiation dose is small. For comparison, the average natural background radiation dose worldwide is 2,400 μSv per year or ~7 μSv per day, and a round trip airplane flight in the U.S. is ~70 μSv. ADDIN EN.CITE <EndNote><Cite><Author>International Atomic Energy Agency</Author><Year>2010</Year><RecNum>371</RecNum><DisplayText><style face="superscript">5</style></DisplayText><record><rec-number>371</rec-number><foreign-keys><key app="EN" db-id="vezset9paxw926ev2z0vse5bfdzr2pzvdxap" timestamp="1484172864">371</key></foreign-keys><ref-type name="Electronic Article">43</ref-type><contributors><authors><author>International Atomic Energy Agency,</author></authors></contributors><titles><title>Dual energy x ray absorptiometry for bone mineral density and body composition assessment.</title><secondary-title>IAEA Human Health Series no. 15</secondary-title></titles><periodical><full-title>IAEA Human Health Series no. 15</full-title></periodical><dates><year>2010</year><pub-dates><date>11Jan2017</date></pub-dates></dates><pub-location>Vienna</pub-location><urls><related-urls><url> Measurements are rapid, making this the preferred technique for measurement of bone mineralization in children. Quality control scans are performed daily using a simulated L1-L4 lumbar spine made of hydroxyapatite encased in epoxy resin and thrice weekly using a whole body phantom. The in vitro coefficient of variation is < 1% and the in vivo coefficient in children is < 2%. All scans are reviewed by or under the supervision of the CHPS Nutrition Core Director, Dr. Babette Zemel for quality assurance. The CHPS Nutrition Core is staffed by research technicians who are expertly trained in acquiring DXA scan images in children and adults. Electronic data sets with scan results for bone area, content and density, and body composition from whole body scans are provided to investigators. Peripheral Quantitative Computerized Tomography (pQCT) is a research tool that assesses trabecular and cortical bone dimensions and strength in the peripheral skeleton (Stratec XCT 2000, Birkenfield, Germany). The Stratec XCT 2000 is a rotate-translate QCT device with 12 detectors and a minimum voxel size of 0.4mm. Measurements are typically taken of the distal tibia at the 3%, 38%, and 66% from the distal reference line at the tibia growth plate or can be customized to sites specified by the study investigator. Comparable measurements can be obtained in the distal radius. The 3% site is primarily trabecular and gives a volumetric measure of trabecular BMD. Total volumetric BMD at the 3% site provides an integrated measure of cortical and trabecular density at a distal site. The 38% site provides measures of cortical volumetric BMD, as well as structural parameters such as periosteal and endosteal circumference and cross-sectional moment of inertia (index of bone strength). The 66% site of the tibia is the location of maximal muscle circumference and will be used to evaluate the effect of local body composition (i.e., muscle cross-sectional area) on bone. Alternate measurement sites at fixed or relative distances from the reference landmark can be obtained at the request of the investigator. The effective radiation dose for the p-QCT measurements is very low (< 0.01?Sv). Phantoms are scanned daily to monitor quality control of the device. The CHPS Nutrition Core Director, Dr. Babette Zemel, reviews all scans for quality assurance. The coefficient of variation for QCT measurements in children range between 0.5 to 2.8%PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5HaWxzYW56PC9BdXRob3I+PFllYXI+MTk5ODwvWWVhcj48

UmVjTnVtPjQ0MzwvUmVjTnVtPjxEaXNwbGF5VGV4dD48c3R5bGUgZmFjZT0ic3VwZXJzY3JpcHQi

PjctOTwvc3R5bGU+PC9EaXNwbGF5VGV4dD48cmVjb3JkPjxyZWMtbnVtYmVyPjQyPC9yZWMtbnVt

YmVyPjxyZWYtdHlwZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48Y29udHJp

YnV0b3JzPjxhdXRob3JzPjxhdXRob3I+R2lsc2FueiwgVi48L2F1dGhvcj48L2F1dGhvcnM+PC9j

b250cmlidXRvcnM+PGF1dGgtYWRkcmVzcz5SYWRpb2xvZ3kgRGVwYXJ0bWVudCwgQ2hpbGRyZW4m

YXBvcztzIEhvc3BpdGFsIExvcyBBbmdlbGVzLCBDQSA5MDAyNywgVVNBLiBnaWxzYW56QGhzYy51

c2MuZWR1PC9hdXRoLWFkZHJlc3M+PHRpdGxlcz48dGl0bGU+Qm9uZSBkZW5zaXR5IGluIGNoaWxk

cmVuOiBhIHJldmlldyBvZiB0aGUgYXZhaWxhYmxlIHRlY2huaXF1ZXMgYW5kIGluZGljYXRpb25z

PC90aXRsZT48c2Vjb25kYXJ5LXRpdGxlPkV1ciBKIFJhZGlvbDwvc2Vjb25kYXJ5LXRpdGxlPjxh

bHQtdGl0bGU+RXVyb3BlYW4gam91cm5hbCBvZiByYWRpb2xvZ3k8L2FsdC10aXRsZT48L3RpdGxl

cz48cGFnZXM+MTc3LTgyPC9wYWdlcz48dm9sdW1lPjI2PC92b2x1bWU+PG51bWJlcj4yPC9udW1i

ZXI+PGtleXdvcmRzPjxrZXl3b3JkPipCb25lIERlbnNpdHk8L2tleXdvcmQ+PGtleXdvcmQ+Qm9u

ZSBhbmQgQm9uZXMvKnJhZGlvZ3JhcGh5PC9rZXl3b3JkPjxrZXl3b3JkPkNoaWxkPC9rZXl3b3Jk

PjxrZXl3b3JkPkRlbnNpdG9tZXRyeSwgWC1SYXk8L2tleXdvcmQ+PGtleXdvcmQ+SHVtYW5zPC9r

ZXl3b3JkPjxrZXl3b3JkPlJlc2VhcmNoIFN1cHBvcnQsIE5vbi1VLlMuIEdvdiZhcG9zO3Q8L2tl

eXdvcmQ+PGtleXdvcmQ+UmVzZWFyY2ggU3VwcG9ydCwgVS5TLiBHb3YmYXBvczt0LCBQLkguUy48

L2tleXdvcmQ+PGtleXdvcmQ+VG9tb2dyYXBoeSwgWC1SYXkgQ29tcHV0ZWQ8L2tleXdvcmQ+PC9r

ZXl3b3Jkcz48ZGF0ZXM+PHllYXI+MTk5ODwveWVhcj48cHViLWRhdGVzPjxkYXRlPkphbjwvZGF0

ZT48L3B1Yi1kYXRlcz48L2RhdGVzPjxpc2JuPjA3MjAtMDQ4WCAoUHJpbnQpPC9pc2JuPjxhY2Nl

c3Npb24tbnVtPjk1MTgyMjY8L2FjY2Vzc2lvbi1udW0+PHVybHM+PHJlbGF0ZWQtdXJscz48dXJs

Pmh0dHA6Ly93d3cubmNiaS5ubG0ubmloLmdvdi9lbnRyZXovcXVlcnkuZmNnaT9jbWQ9UmV0cmll

dmUmYW1wO2RiPVB1Yk1lZCZhbXA7ZG9wdD1DaXRhdGlvbiZhbXA7bGlzdF91aWRzPTk1MTgyMjYg

PC91cmw+PC9yZWxhdGVkLXVybHM+PC91cmxzPjxsYW5ndWFnZT5lbmc8L2xhbmd1YWdlPjwvcmVj

b3JkPjwvQ2l0ZT48Q2l0ZT48QXV0aG9yPlNjaG9uYXU8L0F1dGhvcj48WWVhcj4xOTk4PC9ZZWFy

PjxSZWNOdW0+NDQ0PC9SZWNOdW0+PHJlY29yZD48cmVjLW51bWJlcj4xMzE8L3JlYy1udW1iZXI+

PHJlZi10eXBlIG5hbWU9IkpvdXJuYWwgQXJ0aWNsZSI+MTc8L3JlZi10eXBlPjxjb250cmlidXRv

cnM+PGF1dGhvcnM+PGF1dGhvcj5TY2hvbmF1LCBFLjwvYXV0aG9yPjwvYXV0aG9ycz48L2NvbnRy

aWJ1dG9ycz48YXV0aC1hZGRyZXNzPlVuaXZlcnNpdHkgQ2hpbGRyZW4mYXBvcztzIEhvc3BpdGFs

IENvbG9nbmUsIEdlcm1hbnkuPC9hdXRoLWFkZHJlc3M+PHRpdGxlcz48dGl0bGU+UHJvYmxlbXMg

b2YgYm9uZSBhbmFseXNpcyBpbiBjaGlsZGhvb2QgYW5kIGFkb2xlc2NlbmNlPC90aXRsZT48c2Vj

b25kYXJ5LXRpdGxlPlBlZGlhdHIgTmVwaHJvbDwvc2Vjb25kYXJ5LXRpdGxlPjwvdGl0bGVzPjxw

YWdlcz40MjAtOTwvcGFnZXM+PHZvbHVtZT4xMjwvdm9sdW1lPjxudW1iZXI+NTwvbnVtYmVyPjxk

YXRlcz48eWVhcj4xOTk4PC95ZWFyPjxwdWItZGF0ZXM+PGRhdGU+SnVuPC9kYXRlPjwvcHViLWRh

dGVzPjwvZGF0ZXM+PGFjY2Vzc2lvbi1udW0+OTY4Njk2NTwvYWNjZXNzaW9uLW51bT48dXJscz48

cmVsYXRlZC11cmxzPjx1cmw+aHR0cDovL3d3dy5uY2JpLm5sbS5uaWguZ292L2VudHJlei9xdWVy

eS5mY2dpP2NtZD1SZXRyaWV2ZSZhbXA7ZGI9UHViTWVkJmFtcDtkb3B0PUNpdGF0aW9uJmFtcDts

aXN0X3VpZHM9OTY4Njk2NTwvdXJsPjwvcmVsYXRlZC11cmxzPjwvdXJscz48L3JlY29yZD48L0Np

dGU+PENpdGU+PEF1dGhvcj5aZW1lbDwvQXV0aG9yPjxZZWFyPjIwMDQ8L1llYXI+PFJlY051bT4z

MTY2PC9SZWNOdW0+PHJlY29yZD48cmVjLW51bWJlcj4zMTY2PC9yZWMtbnVtYmVyPjxyZWYtdHlw

ZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48Y29udHJpYnV0b3JzPjxhdXRo

b3JzPjxhdXRob3I+WmVtZWwsIEIuIFMuPC9hdXRob3I+PGF1dGhvcj5QYXVsaGFtdXMsIEQuPC9h

dXRob3I+PGF1dGhvcj5EaWx6ZXIsIEMuPC9hdXRob3I+PGF1dGhvcj5TdGFsbGluZ3MsIFYuIEEu

PC9hdXRob3I+PGF1dGhvcj5TaGFiYm91dCwgTS48L2F1dGhvcj48YXV0aG9yPkxlb25hcmQsIE0u

IEIuPC9hdXRob3I+PC9hdXRob3JzPjwvY29udHJpYnV0b3JzPjx0aXRsZXM+PHRpdGxlPlByZWNp

c2lvbiBvZiBwZXJpcGhlcmFsIHF1YW50aXRhdGl2ZSBjb21wdXRlZCB0b21vZ3JhcGh5IG1lYXN1

cmVzIG9mIHRoZSB0aWJpYSBpbiBjaGlsZHJlbjwvdGl0bGU+PHNlY29uZGFyeS10aXRsZT5KIEJv

bmUgTWluZXIgUmVzPC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+PHBlcmlvZGljYWw+PGZ1bGwt

dGl0bGU+Sm91cm5hbCBvZiBCb25lIGFuZCBNaW5lcmFsIFJlc2VhcmNoPC9mdWxsLXRpdGxlPjxh

YmJyLTE+Si4gQm9uZSBNaW5lci4gUmVzLjwvYWJici0xPjxhYmJyLTI+SiBCb25lIE1pbmVyIFJl

czwvYWJici0yPjwvcGVyaW9kaWNhbD48cGFnZXM+UzIzMjwvcGFnZXM+PHZvbHVtZT4xOTwvdm9s

dW1lPjxudW1iZXI+U3VwcGwgMTwvbnVtYmVyPjxkYXRlcz48eWVhcj4yMDA0PC95ZWFyPjwvZGF0

ZXM+PHVybHM+PC91cmxzPjwvcmVjb3JkPjwvQ2l0ZT48L0VuZE5vdGU+

ADDIN EN.CITE PEVuZE5vdGU+PENpdGU+PEF1dGhvcj5HaWxzYW56PC9BdXRob3I+PFllYXI+MTk5ODwvWWVhcj48

UmVjTnVtPjQ0MzwvUmVjTnVtPjxEaXNwbGF5VGV4dD48c3R5bGUgZmFjZT0ic3VwZXJzY3JpcHQi

PjctOTwvc3R5bGU+PC9EaXNwbGF5VGV4dD48cmVjb3JkPjxyZWMtbnVtYmVyPjQyPC9yZWMtbnVt

YmVyPjxyZWYtdHlwZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48Y29udHJp

YnV0b3JzPjxhdXRob3JzPjxhdXRob3I+R2lsc2FueiwgVi48L2F1dGhvcj48L2F1dGhvcnM+PC9j

b250cmlidXRvcnM+PGF1dGgtYWRkcmVzcz5SYWRpb2xvZ3kgRGVwYXJ0bWVudCwgQ2hpbGRyZW4m

YXBvcztzIEhvc3BpdGFsIExvcyBBbmdlbGVzLCBDQSA5MDAyNywgVVNBLiBnaWxzYW56QGhzYy51

c2MuZWR1PC9hdXRoLWFkZHJlc3M+PHRpdGxlcz48dGl0bGU+Qm9uZSBkZW5zaXR5IGluIGNoaWxk

cmVuOiBhIHJldmlldyBvZiB0aGUgYXZhaWxhYmxlIHRlY2huaXF1ZXMgYW5kIGluZGljYXRpb25z

PC90aXRsZT48c2Vjb25kYXJ5LXRpdGxlPkV1ciBKIFJhZGlvbDwvc2Vjb25kYXJ5LXRpdGxlPjxh

bHQtdGl0bGU+RXVyb3BlYW4gam91cm5hbCBvZiByYWRpb2xvZ3k8L2FsdC10aXRsZT48L3RpdGxl

cz48cGFnZXM+MTc3LTgyPC9wYWdlcz48dm9sdW1lPjI2PC92b2x1bWU+PG51bWJlcj4yPC9udW1i

ZXI+PGtleXdvcmRzPjxrZXl3b3JkPipCb25lIERlbnNpdHk8L2tleXdvcmQ+PGtleXdvcmQ+Qm9u

ZSBhbmQgQm9uZXMvKnJhZGlvZ3JhcGh5PC9rZXl3b3JkPjxrZXl3b3JkPkNoaWxkPC9rZXl3b3Jk

PjxrZXl3b3JkPkRlbnNpdG9tZXRyeSwgWC1SYXk8L2tleXdvcmQ+PGtleXdvcmQ+SHVtYW5zPC9r

ZXl3b3JkPjxrZXl3b3JkPlJlc2VhcmNoIFN1cHBvcnQsIE5vbi1VLlMuIEdvdiZhcG9zO3Q8L2tl

eXdvcmQ+PGtleXdvcmQ+UmVzZWFyY2ggU3VwcG9ydCwgVS5TLiBHb3YmYXBvczt0LCBQLkguUy48

L2tleXdvcmQ+PGtleXdvcmQ+VG9tb2dyYXBoeSwgWC1SYXkgQ29tcHV0ZWQ8L2tleXdvcmQ+PC9r

ZXl3b3Jkcz48ZGF0ZXM+PHllYXI+MTk5ODwveWVhcj48cHViLWRhdGVzPjxkYXRlPkphbjwvZGF0

ZT48L3B1Yi1kYXRlcz48L2RhdGVzPjxpc2JuPjA3MjAtMDQ4WCAoUHJpbnQpPC9pc2JuPjxhY2Nl

c3Npb24tbnVtPjk1MTgyMjY8L2FjY2Vzc2lvbi1udW0+PHVybHM+PHJlbGF0ZWQtdXJscz48dXJs

Pmh0dHA6Ly93d3cubmNiaS5ubG0ubmloLmdvdi9lbnRyZXovcXVlcnkuZmNnaT9jbWQ9UmV0cmll

dmUmYW1wO2RiPVB1Yk1lZCZhbXA7ZG9wdD1DaXRhdGlvbiZhbXA7bGlzdF91aWRzPTk1MTgyMjYg

PC91cmw+PC9yZWxhdGVkLXVybHM+PC91cmxzPjxsYW5ndWFnZT5lbmc8L2xhbmd1YWdlPjwvcmVj

b3JkPjwvQ2l0ZT48Q2l0ZT48QXV0aG9yPlNjaG9uYXU8L0F1dGhvcj48WWVhcj4xOTk4PC9ZZWFy

PjxSZWNOdW0+NDQ0PC9SZWNOdW0+PHJlY29yZD48cmVjLW51bWJlcj4xMzE8L3JlYy1udW1iZXI+

PHJlZi10eXBlIG5hbWU9IkpvdXJuYWwgQXJ0aWNsZSI+MTc8L3JlZi10eXBlPjxjb250cmlidXRv

cnM+PGF1dGhvcnM+PGF1dGhvcj5TY2hvbmF1LCBFLjwvYXV0aG9yPjwvYXV0aG9ycz48L2NvbnRy

aWJ1dG9ycz48YXV0aC1hZGRyZXNzPlVuaXZlcnNpdHkgQ2hpbGRyZW4mYXBvcztzIEhvc3BpdGFs

IENvbG9nbmUsIEdlcm1hbnkuPC9hdXRoLWFkZHJlc3M+PHRpdGxlcz48dGl0bGU+UHJvYmxlbXMg

b2YgYm9uZSBhbmFseXNpcyBpbiBjaGlsZGhvb2QgYW5kIGFkb2xlc2NlbmNlPC90aXRsZT48c2Vj

b25kYXJ5LXRpdGxlPlBlZGlhdHIgTmVwaHJvbDwvc2Vjb25kYXJ5LXRpdGxlPjwvdGl0bGVzPjxw

YWdlcz40MjAtOTwvcGFnZXM+PHZvbHVtZT4xMjwvdm9sdW1lPjxudW1iZXI+NTwvbnVtYmVyPjxk

YXRlcz48eWVhcj4xOTk4PC95ZWFyPjxwdWItZGF0ZXM+PGRhdGU+SnVuPC9kYXRlPjwvcHViLWRh

dGVzPjwvZGF0ZXM+PGFjY2Vzc2lvbi1udW0+OTY4Njk2NTwvYWNjZXNzaW9uLW51bT48dXJscz48

cmVsYXRlZC11cmxzPjx1cmw+aHR0cDovL3d3dy5uY2JpLm5sbS5uaWguZ292L2VudHJlei9xdWVy

eS5mY2dpP2NtZD1SZXRyaWV2ZSZhbXA7ZGI9UHViTWVkJmFtcDtkb3B0PUNpdGF0aW9uJmFtcDts

aXN0X3VpZHM9OTY4Njk2NTwvdXJsPjwvcmVsYXRlZC11cmxzPjwvdXJscz48L3JlY29yZD48L0Np

dGU+PENpdGU+PEF1dGhvcj5aZW1lbDwvQXV0aG9yPjxZZWFyPjIwMDQ8L1llYXI+PFJlY051bT4z

MTY2PC9SZWNOdW0+PHJlY29yZD48cmVjLW51bWJlcj4zMTY2PC9yZWMtbnVtYmVyPjxyZWYtdHlw

ZSBuYW1lPSJKb3VybmFsIEFydGljbGUiPjE3PC9yZWYtdHlwZT48Y29udHJpYnV0b3JzPjxhdXRo

b3JzPjxhdXRob3I+WmVtZWwsIEIuIFMuPC9hdXRob3I+PGF1dGhvcj5QYXVsaGFtdXMsIEQuPC9h

dXRob3I+PGF1dGhvcj5EaWx6ZXIsIEMuPC9hdXRob3I+PGF1dGhvcj5TdGFsbGluZ3MsIFYuIEEu

PC9hdXRob3I+PGF1dGhvcj5TaGFiYm91dCwgTS48L2F1dGhvcj48YXV0aG9yPkxlb25hcmQsIE0u

IEIuPC9hdXRob3I+PC9hdXRob3JzPjwvY29udHJpYnV0b3JzPjx0aXRsZXM+PHRpdGxlPlByZWNp

c2lvbiBvZiBwZXJpcGhlcmFsIHF1YW50aXRhdGl2ZSBjb21wdXRlZCB0b21vZ3JhcGh5IG1lYXN1

cmVzIG9mIHRoZSB0aWJpYSBpbiBjaGlsZHJlbjwvdGl0bGU+PHNlY29uZGFyeS10aXRsZT5KIEJv

bmUgTWluZXIgUmVzPC9zZWNvbmRhcnktdGl0bGU+PC90aXRsZXM+PHBlcmlvZGljYWw+PGZ1bGwt

dGl0bGU+Sm91cm5hbCBvZiBCb25lIGFuZCBNaW5lcmFsIFJlc2VhcmNoPC9mdWxsLXRpdGxlPjxh

YmJyLTE+Si4gQm9uZSBNaW5lci4gUmVzLjwvYWJici0xPjxhYmJyLTI+SiBCb25lIE1pbmVyIFJl

czwvYWJici0yPjwvcGVyaW9kaWNhbD48cGFnZXM+UzIzMjwvcGFnZXM+PHZvbHVtZT4xOTwvdm9s

dW1lPjxudW1iZXI+U3VwcGwgMTwvbnVtYmVyPjxkYXRlcz48eWVhcj4yMDA0PC95ZWFyPjwvZGF0

ZXM+PHVybHM+PC91cmxzPjwvcmVjb3JkPjwvQ2l0ZT48L0VuZE5vdGU+

ADDIN EN.CITE.DATA 7-9. The procedure takes approximately 15 minutes to complete depending on the number of sites scanned. Local reference data is available on approximately 500 to 700 healthy control children.The CHPS Nutrition Core is equipped with two research dedicated pQCT devices, one in the satellite CHPS facility at 3550 Market Street, and the other in the main facility at the Children’s Hospital of Philadelphia. The CHPS Nutrition Core is staffed by research technicians who are expertly trained in acquiring pQCT scan images in children and adults. Electronic data sets of scan results with quality assurance ratings and derived measures of cortical and trabecular bone density, geometry, and strength are provided to investigators.High Resolution Quantitative Computerized Tomography (HR-QCT)HR-QCT provides sufficient resolution for 3D in vivo imaging of bone. The Xtreme CT II (SCANCO Medical AG, Bruettisellen, Switzerland) yields 3D measurements of bone geometric parameters and cortical and trabecular microarchitecture that correlate with bone strength10-15. It uses a low dose x-ray (less than 5 μSv ADDIN EN.CITE <EndNote><Cite><Author>Burrows</Author><Year>2010</Year><RecNum>375</RecNum><DisplayText><style face="superscript">10</style></DisplayText><record><rec-number>375</rec-number><foreign-keys><key app="EN" db-id="vezset9paxw926ev2z0vse5bfdzr2pzvdxap" timestamp="1484173579">375</key></foreign-keys><ref-type name="Journal Article">17</ref-type><contributors><authors><author>Burrows, M.</author><author>Liu, D.</author><author>McKay, H.</author></authors></contributors><auth-address>Department of Orthopedics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada. Melonie.burrows@ubc.ca</auth-address><titles><title>High-resolution peripheral QCT imaging of bone micro-structure in adolescents</title><secondary-title>Osteoporos Int</secondary-title></titles><periodical><full-title>Osteoporos Int</full-title></periodical><pages>515-20</pages><volume>21</volume><number>3</number><keywords><keyword>Adolescent</keyword><keyword>Bone Density/physiology</keyword><keyword>Bone and Bones/*diagnostic imaging/physiology/ultrastructure</keyword><keyword>Feasibility Studies</keyword><keyword>Female</keyword><keyword>Growth Plate/diagnostic imaging/physiology/ultrastructure</keyword><keyword>Humans</keyword><keyword>Male</keyword><keyword>Radiation Dosage</keyword><keyword>Tibia/diagnostic imaging/ultrastructure</keyword><keyword>Tomography, X-Ray Computed/methods</keyword><keyword>Young Adult</keyword></keywords><dates><year>2010</year><pub-dates><date>Mar</date></pub-dates></dates><isbn>1433-2965 (Electronic)&#xD;0937-941X (Linking)</isbn><accession-num>19322507</accession-num><urls><related-urls><url>) to measure both volumetric bone density and microarchitecture. The scanner is located at the satellite CHPS at 3550 Market Street location and is operated by trained staff under the supervision of Dr. Zemel. Phantoms are scanned daily to monitor quality control of the device.Each scan of the distal radius or tibia takes less than 4 minutes, and a complete visit, including instructions to patients, scout view, and full scans of both the distal radius and tibia requires less than 30 minutes. The analysis procedure calculates cortical and trabecular vBMD, geometry, and microstructure.MEASURES OF MUSCLE STRENGTHThe Biodex Dynamometer: (Biodex Medical Systems., Shirley, NY) measures muscular strength across joints. The procedure requires a standardized period of warm-up consisting of 5 minutes of treadmill walking. The study participant then performs an isometric strength test. Typically, plantar flexion and dorsiflexion of the foot are measured although other sites are possible. For the ankle, a maximal pain free range of motion (ROM) is established with the left knee in a neutral position. The subject is then assessed in 1 to 4 positions depending on the protocol requirements and the total available ROM: (1) 10 degrees of dorsiflexion, (2) neutral, (3) 10 degrees plantar flexion, and (4) 20 degrees plantar flexion. Three repetitions of isometric plantar flexion and dorsiflexion are performed at each position. A five-second rest is given between repetitions and a 20-second rest between sets. At each position, peak torque performance is recorded and saved. Trained technicians perform the test.Hand-Grip Dynamometry: The Smedley III Digital Grip Strength (Takei Scientific Instruments Co., Ltd., Tokyo, Japan) is a hand held device capable of measuring instantaneous hand strength as a function of time for periods of up to 300 seconds. The subject stands upright with arms extended and is instructed to grip the dynamometer and exert full force. Three trials are performed using each hand. The dynamometer digitally displays the force production (kgf) by the subject.Force Plate Jump Mechanography: The Kistler Multicomponent Force Plate (Kistler Instruments AG, Amherst, NY) measures jump power, force, and height, primarily to determine the functional strength and muscle loading of the lower limbs, but other applications are possible. Following a warm-up period consisting of 5 minutes of treadmill walking, the study participant performs the force plate test using a computer driven standardized jump protocol such as for a squat jump or counter-movement jump. The subject first completes three practice jumps followed by three test jumps. An electronic database for each test is generated and provided to the investigator.INDIRECT CALORIMETRY:Resting Energy Expenditure (REE) is assessed by open circuit indirect calorimetry using a VMAX computerized metabolic cart (CareFusion, Yorba Linda, CA). Ideally, tests for children and adults are performed in the early morning in an awake, fasted state, with minimal physical activity prior to the test. A standardized evening meal is recommended, and is designed according to the preferences of the study participant by the Bionutrition Unit’s research dietitians. A 60-minute REE test is performed between 7:00 and 10:00 AM with the subject resting quietly under a clear, plastic hood watching a videotape, after an appropriate period of environmental adjustment. The results are edited to eliminate measurement during the initial period of acclimation to the test, and any other periods of significant physical movement or coughing. The remaining measurements are averaged to obtain the mean REE calculated from the modified Weir equation16, using oxygen consumption, and carbon dioxide production. REE is subsequently compared to predicted values derived from the World Health Organization that adjust for age, gender and weight17 and Schofield equations that adjust for age, gender, weight, and height18. Respiratory quotient is also obtained from the test. For infants, sleeping energy expenditure is measured while napping following a day-time feed. The test can also be used to assess energy expenditure under other circumstances such as the metabolic response to a meal. The metabolic cart is somewhat portable and tests can be performed at the bedside. ADDIN EN.REFLIST 1.Cronk, C., Stallings, V., Spender, Q., Ross, J. & Widdoes, H. Measurement of short term linear growth with a new knee height measuring device. Am J Human Biol 1, 421-428 (1989).2.Morris, N.M. & Udry, J.R. Validation of a self-administered instrument to assess stage of adolescent development. J Youth and Adolesc 9, 271-280 (1980).3.Tanner, J.M. Growth at Adolescence, (Blackwell Scientific Publication, Oxford, 1962).4.Ellis, K.J. et al. Body-composition assessment in infancy: air-displacement plethysmography compared with a reference 4-compartment model. Am J Clin Nutr 85, 90-5 (2007).5.International Atomic Energy Agency. Dual energy x ray absorptiometry for bone mineral density and body composition assessment. in IAEA Human Health Series no. 15 (Vienna, 2010).6.Thomas, S.R., Kalkwarf, H.J., Buckley, D.D. & Heubi, J.E. Effective dose of dual-energy X-ray absorptiometry scans in children as a function of age. J Clin Densitom 8, 415-22 (2005).7.Gilsanz, V. Bone density in children: a review of the available techniques and indications. Eur J Radiol 26, 177-82 (1998).8.Schonau, E. Problems of bone analysis in childhood and adolescence. Pediatr Nephrol 12, 420-9 (1998).9.Zemel, B.S. et al. Precision of peripheral quantitative computed tomography measures of the tibia in children. J Bone Miner Res 19, S232 (2004).10.Burrows, M., Liu, D. & McKay, H. High-resolution peripheral QCT imaging of bone micro-structure in adolescents. Osteoporos Int 21, 515-20 (2010). ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download