The Effect of Leg Length Discrepancy on the Strength of Ankle Muscle

ABSTRACT

OBJECTIVE: This study was designed to evaluate the relation of leg length discrepancy on ankle muscle strength. METHOD: Twenty four adult women were tested (12 leg length equality and 12 leg length discrepancy). Leg length was measured by tape ruler from anterior superior iliac spine to medial malleolus, three times by three different trained examiners. The muscle strength (bilateral ankle dorsiflexors and plantarflexors) was measured by using Cybex 340 dynamometer at 30 degree/sec and 120 degree/sec. RESULTS: The mean value of leg length discrepancy was 0.89+/-0.24 cm. In leg length discrepancy group, the peak torque of ankle plantarflexor were 44.50+/-20.94 Nm in long leg and 51.83+/-12.75 Nm in short leg at 30 degree/sec angular velocity (p<0.05). CONCLUSION: We concluded that there were significant increase in plantar flexor peak torques of short leg than those of long legs at 30 degree/sec (P<0.05). Perhaps the difference of the muscle strength might be due to compensatory mechanism of short leg in propulsion during gait.