Isokinetic and isometric strength of the thigh muscles in below-knee amputees

Objective. The strength of the quadriceps and hamstring muscles of the amputated limb in below-knee amputees was evaluated. Design. A descriptive study based on clinical measurements of muscle strength. Background. The residual limb of below-knee amputees is less active in daily functions. As a result, atrophy of the thigh muscles in the affected limb is a common finding. Quality of standing and gait performances depend on the strength of these muscles, which activate the knee of the amputated limb. Methods. Isokinetic concentric and eccentric, as well as isometric, strength of thigh muscles was measured by means of a dynamometer. Parameters of peak torque and maximal average torque of the quadriceps and hamstring muscles were considered. Results. Significant decreases (P < 0.01) in strength of the quadriceps and hamstrings were observed in the amputated limb. Thigh muscle strength in amputees over 7 years was not significantly weaker when compared with amputees where amputation had been performed more recently. Conclusions. In below-knee amputees, the thigh muscle strength of the amputated limb decreases significantly during the first years after amputation.