Sex Differences in Muscle Activity During Drop-Jump Landing Motion

This study investigated the effect of hip joint muscles' activity on dynamic knee-joint valgus angle during one-leg drop-jump landing motion in male and female subjects. Twenty-four healthy university students (11 males and 13 females) participated in the study. Surface electromyography was used to measure muscle activity during a one-leg landing motion. A gender difference was observed: males showed greater activity in the gluteus medius muscle compared to the adductor magnus muscle, whereas females showed greater activity in the rectus femoris muscle. A correlation between lower limb muscle activity and knee-joint valgus angle was found in male subjects but not in female subjects, suggesting that factors other than muscle activity are necessary for controlling knee joint valgus in females. Therefore, factors other than muscle activity should be investigated in the future to prevent female anterior cruciate ligament injuries.