Are There Differences Between Sexes in Performance-Related Variables During a Maximal Intermittent Flywheel Test?

Area of Science:

• Sports Science
• Human Physiology
• Biomechanics

Background:

• Previous studies on sex differences in fatigability used low-to-moderate intensity tasks.
• Maximal exertions using flywheel devices (FDs) have not been extensively studied for sex-based fatigue differences.

Purpose of the Study:

• To identify sex differences in fatigue-related performance during a maximal intermittent fatiguing protocol using a FD.
• To determine the most sensitive dynamometric and mechanical variables for assessing fatigue in both males and females.

Main Methods:

• A cohort observational study involving 34 young adults (17 female/17 male).
• Participants performed a maximal intermittent half-squat exercise protocol on a FD for 10 sets of 10 repetitions with 3-minute recovery.
• Analysis included inter- and intraset changes in force, power, velocity, work, and impulse, with and without body mass normalization.

Main Results:

• Men exhibited greater and earlier performance decrements than women (P < .05), but these sex differences were not significant after normalizing for body mass (P > .05).
• Intraset analysis showed higher relative changes in the final set (P ≤ .03).
• Power was the most sensitive variable for detecting performance decline (P ≤ .04).

Conclusions:

• Women demonstrate slower and delayed fatigue kinetics compared to men in maximal intermittent FD protocols when body dimensionality is not considered.
• Power output is the most sensitive and discriminative variable for assessing performance decreases during maximal exertion on FDs.
• Body mass normalization is crucial for accurate sex comparisons in FD performance.