Sex differences in lower limb movement variability during a fatiguing repetitive loading task

This study evaluated differences in lower limb joint coupling variability between recreationally-active male (n = 21) and female participants (n = 20) during single-leg hopping to exhaustion. Spatio-temporal characteristics and variability of the knee-ankle and hip-knee joint couplings were determined over the duration of hopping. As fatigue progressed joint coupling variability increased by a greater magnitude in females compared to males. Females had significantly lower variability compared to males in the knee-ankle couplings during the propulsion phase at the beginning of the trial but this effect progressively disappeared during the trial. These findings suggest that as fatigue progresses, there is a regression to a similar magnitude of joint coupling variability which may represent a common level of synchronous joint interaction between sexes.