Muscle fatigue in response to low-load blood flow-restricted elbow-flexion exercise: are there any sex differences?

Abstract

This study aimed to determine whether men and women display a different magnitude of muscle fatigue in response to high-load (HL) and low-load blood flow-restricted (LLBFR) elbow-flexion exercise. We also explored to which extent both exercise protocols induce similar levels of muscle fatigue (i.e., torque decrement). Sixty-two young participants (31 men and 31 women) performed dynamic elbow flexions at 20 and 75% of one-repetition maximum for LLBFR and HL exercise, respectively. Maximum voluntary isometric contractions were performed before and after exercise to quantify muscle fatigue. Men and women exhibited similar magnitude of relative torque decrement after both exercise protocols (p > 0.05). HL was more fatiguing (∆ torque output: 11.9 and 23N.m in women and men, respectively) than LLBFR resistance exercise (∆ torque output: 8.3 and 15.4N.m in women and men, respectively) in both sexes, but this was largely attenuated after controlling for the differences in volume load between protocols (p > 0.05). These data show that torque decrement in response to LLBFR and HL dynamic elbow-flexion exercise does not follow a sexually dimorphic pattern. Our data also indicate that, if performed in a multiple-set fashion and prescribed for a given volume load, elbow-flexion LLBFR exercise induces similar levels of fatigue as HL acute training. Importantly, this occurs similarly in both sexes.