No sex differences in evoked contractile properties after fatiguing isometric and isotonic exercise for the plantar flexors.
Year: 2022
Type: article
Abstract: OBJECTIVES: Females tend to fatigue less than males after isometric exercise, but less is clear for isotonic exercise. Further, there have been relatively few sex comparisons for fatigability of the plantar flexors (PFs). We sought to investigate potential sex differences in contractile properties after a sustained maximal voluntary isometric contraction (MVIC) and isotonic contractions. METHODS: Twenty-seven physically active males (n=14; 22±2 yrs) and females (n=13; 21±2 yrs) randomly performed a 2 min MVIC and 120 concentric isotonic (30% MVIC) contractions for the PFs on separate visits. Before and after each fatiguing task, muscle activation was obtained from brief MVICs, which was followed (~2 sec) by tibial nerve stimulation at rest. Contractile properties including peak twitch, absolute and normalized time to peak twitch, and half relaxation time were calculated. RESULTS: =0.06-0.94). CONCLUSIONS: Peripheral fatigue, as indicated by contractile parameters, did not differ between sexes after isometric or isotonic exercise. The PFs similar fiber type proportions between sexes or greater fiber type heterogeneity may explain why sex differences in fatigability, though common in other muscle groups (e.g., knee extensors), were not expressed in this muscle group.
Source: PubMed Central
Authors: Phuong L Ha, Benjamin E Dalton, Michaela G Alesi, Tyler M Smith, Trisha A VanDusseldorp, Yuri Feito, Garrett M Hester
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W4311283723