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Thigh muscle strength in below-knee amputees
Scandinavian Journal of Rehabilitation Medicine. Supplement
|January 1, 1983
Summary
Below-knee amputees experience reduced thigh muscle strength, which is linked to muscle atrophy and impacts walking ability. Preserved strength in amputated legs correlates with better walking capacity.
Area of Science:
- Biomechanics
- Rehabilitation Medicine
- Kinesiology
Background:
- Below-knee amputation often leads to decreased lower limb muscle strength.
- Muscle atrophy and altered motor unit recruitment are potential contributors to strength deficits.
Purpose of the Study:
- To quantify thigh muscle strength reduction in below-knee amputees.
- To correlate muscle strength with muscle atrophy and clinical function.
Main Methods:
- Isometric and isokinetic knee strength testing using an isokinetic dynamometer (Cybex II).
- Muscle atrophy assessment via muscle biopsies (vastus lateralis) and computed tomography (quadriceps and hamstring cross-sectional areas).
Main Results:
- Amputated leg strength (knee extension/flexion) was significantly lower than the non-amputated leg.
- Strength correlated with vastus lateralis muscle fiber area but not overall quadriceps cross-sectional area.
- Strength reduction exceeded muscle atrophy, suggesting motor unit recruitment changes are also significant.
Conclusions:
- Muscle atrophy and altered motor unit recruitment contribute to strength loss in below-knee amputees.
- Preserved thigh muscle strength in the amputated leg is associated with better walking capacity (step length, walking speed).