Sustained isometric contractions at 20% MVC resulted in a shorter time to task failure in men compared to women, whereas the 80% MVC task showed no sex difference in time to failure.
Does the intensity of sustained isometric contraction affect time to task failure and voluntary activation differently in men and women?
Low-force, long-duration fatiguing contractions induce greater central fatigue than high-force contractions in both men and women, with women showing longer time to task failure at low forces.
The magnitude of failure in voluntary drive after fatiguing contractions of different intensities in men and women is not known. The purpose of this study was to compare the time to task failure and voluntary activation of men and women for a sustained isometric contraction performed at a low and high intensity with the elbow flexor muscles. Nine men and nine women sustained an isometric contraction at 20% and 80% of maximal voluntary contraction (MVC) force until task failure during separate sessions. The men had a shorter time to failure than women for the 20% but not the 80% MVC task. Voluntary activation was reduced to similar levels for the men and women at the end of the fatiguing contractions but was reduced less after the 80% MVC task than the 20% MVC contraction. Twitch amplitude was reduced similarly at task failure for both sexes and to similar levels at termination of the 20% and 80% MVC tasks. The rate of change in mean arterial pressure was the main predictor of time to failure for the low-force sustained contraction. These results suggest that women experienced greater muscle perfusion, less peripheral fatigue, and a longer time to task failure than men during the low-force fatiguing contraction. However, the low-force task induced greater central fatigue than the high-force contraction for both men and women. Thus, low-force, long-duration fatiguing contractions can be used in rehabilitation to induce significant fatigue within the central nervous system and potentially greater neural adaptations in men and women.
Yoon et al. (Wed,) reported a other. Sustained isometric contraction vs. Men vs Women was evaluated on Time to task failure and voluntary activation. Sustained isometric contractions at 20% MVC resulted in a shorter time to task failure in men compared to women, whereas the 80% MVC task showed no sex difference in time to failure.