Gender influences neuromuscular adaptations to muscle unloading

Muscle unloading results in decreased strength. This is partly attributed to reduced neural activation. This study examined whether men and women experienced different adaptations to muscle unloading. Ten men (21.4 +/- 0.8 years; mean +/- SE) and ten women (20.9 +/- 0.2 years) were subjected to 1 week of muscle unloading. Muscle function was quantified during knee extensions before, and following unloading. Electromyography (EMG) was assessed during maximal isometric contractions before, and after unloading. Results showed greater (P < 0.05) unloading-induced decrement in muscle performance in women than men. The loss of peak torque was significantly correlated (r = 0.69) with the decline in EMG consequent to unloading, and women displayed significantly larger reductions in EMG. These findings indicate that: (1) women are more affected by muscle unloading than men, and (2) gender-related differences in strength declines are associated with similar disparities in the nervous system's capacity to maximally stimulate muscle.