Neuromuscular fatigue in men and women during severe-intensity exercise.

The aim of this study was to explore sex differences in neuromuscular fatigue during a severe-intensity cycling exercise. Twenty-four healthy participants (12 women and 12 men) cycled at 80% of the difference between gas exchange threshold and maximal power output to the limit of tolerance. Neuromuscular fatigue was assessed by the decrease in maximal voluntary contraction of the knee extensors before and after exercise, and central and peripheral fatigue was measured by the decrease in voluntary activation and quadriceps potentiated twitch force before and after exercise. Women presented shorter time to task failure (P=0.025) and lower levels of neuromuscular fatigue (P=0.006) and peripheral fatigue (P<0.001) than men. Women and men showed different patterns of muscle activation during exercise, with women presenting greater muscle activation at the beginning of exercise and sustaining this elevated muscle activation throughout exercise, while men increased muscle activation from the beginning to the end of exercise. In conclusion, women had lower levels of neuromuscular fatigue, mainly caused by lower levels of peripheral fatigue, and a different muscle activation pattern in an exhaustive severe-intensity cycling exercise.