Simulating Quadriceps Muscle Atrophy and Activation ...

Simulating Quadriceps Muscle Atrophy and Activation Deficits during Gait

Can't hear us? Select Audio -> Integrated VoIP

-> Join Conference

Julie Thompson Stanford University

Simulating Quadriceps Muscle Atrophy and Activation Deficits during Gait

5

Webinar Objectives

? Background on prevalence of quadriceps muscle weakness

? 2 types of weakness: atrophy and activation deficit

? Motivating questions ? How we addressed questions using OpenSim ? Methodological details of simulating weakness ? Major findings and take-away

? Thompson et al., Journal of Biomechanics; 46(13): 2165-72, 2013.

6

Background

? Osteoarthritis (OA):

? musculoskeletal disease ? progressive deterioration of the

articular cartilage of the joint

? Very Common

? 49.9 million in U.S. (22.2% of the population) between 2007 and 20091

? 67 million (25%) by 20302 ? 37% over age 60 have

radiographic evidence of OA3



1. MMWR, 59: 1261-65, 2010.



2. Hootman et al., Arthr Rheum 54: 226-29, 2006.

7

3. Dillon et al., J Rheumatol 33: 2271-79, 2006.

Background

? Approximately 21.1 million adults in the U.S. report activity limitations due to symptoms of arthritis1

? Increased dependence and difficulty during activities2:

? Climbing stairs, Walking





Healthsharenews.

1. MMWR, 59: 1261-65, 2010.

3. Lord et al., J Am Geriatr Soc 47: 1077-81, 1999.



4. Moxley Scarborough et al., Gait Posture 10: 10-20, 1999. anatomyart/quads.htm

8

2. Fisher et al., SJRM 29: 213-21, 1997. 5. Walsh et al., Phys Ther 78: 248-58, 1998.

Background

? Approximately 21.1 million adults in the U.S. report activity limitations due to symptoms of arthritis1

? Increased dependence and difficulty during activities2:

? Climbing stairs, Walking

pelvis

? Quadriceps weakness, in particular, has been linked to functional impairment3-5

? Increased fall risk ? slower walking speed





knee

Healthsharenews.

1. MMWR, 59: 1261-65, 2010.

3. Lord et al., J Am Geriatr Soc 47: 1077-81, 1999.



4. Moxley Scarborough et al., Gait Posture 10: 10-20, 1999. anatomyart/quads.htm

9

2. Fisher et al., SJRM 29: 213-21, 1997. 5. Walsh et al., Phys Ther 78: 248-58, 1998.

Quadriceps Weakness

? Quadriceps weakness is one of the earliest and most common symptoms of OA1

? Two sources of muscle weakness:

? Atrophy

? Decrease in number or size of muscle fibers

? Reduced voluntary activation

? Inability to recruit (activate) all of the muscle's motor units2 (groupings of muscle fibers)

1. Fisher et al., Disab Rehab 19: 47-55, 1997.

9

2. Kent-Braun and Le Blanc, Muscle Nerve 19: 861-69, 1996.

Quadriceps Weakness

? Strength deficits

? As high as 38% in late stage OA1 ? As high as 64% after total knee replacement for treatment of knee

OA2

? Activation deficits

? As high as 34% in OA3

? Underlying mechanism relating quadriceps function to gait impairments is unknown

1. Petterson et al., JBJS Am-89: 2327-33, 2007.

2. Mizner et al., Phys Ther 83: 359-65, 2003.

3. Hassan et al., Ann Rheum Dis 60: 612-18, 2001.

10

 ................
................

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

Google Online Preview   Download