Muscle fatigue and electromyographic changes are not different in women and men matched for strength.

Previous gender comparisons of muscle performance have overlooked differences in absolute strength and have studied men and women at similar percentages of their maximal voluntary contraction (MVC). The purpose of this study was to examine agonist and antagonist muscle activation during submaximal fatigue, in men and women matched for strength. We compared plantar flexion muscle performance during a 10-min submaximal (20% MVC) fatigue protocol in ten healthy men and ten healthy women matched for plantar flexor MVC torque output [156.0 (17.6) N m for men and 152.9 (21.7) N m for women, mean (SD), P>0.05]. The results showed that after the fatigue protocol the torque output and the averaged electromyogram (EMG) amplitude of all muscles examined decreased significantly in both genders. The submaximal torque was sustained at the requested level (20% MVC) during the fatiguing contraction by increasing motor unit activity as indicated by the EMG. However, the post hoc tests revealed no significant differences between the two genders in any of the aforementioned tests. The similarity of agonist and antagonist muscle activation during a sustained submaximal contraction in both men and women suggests that the differences in fatigability between the two genders are diminished when the absolute force production is similar.