Sex differences in performance fatigability: evidence from a maximal intermittent protocol using a flywheel device
[eng] The primary aim of this thesis was to compare the mechanisms underlying performance fatigability between males and females following a maximal intermittent fatiguing protocol (IFPmax), consisting of repeated half-squats performed with a flywheel device (FD). The body of the thesis comprises fo...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | Universidad de Barcelona |
| Repositorio: | Dipòsit Digital de la UB |
| OAI Identifier: | oai:diposit.ub.edu:2445/227959 |
| Acceso en línea: | https://hdl.handle.net/2445/227959 http://hdl.handle.net/10803/696932 |
| Access Level: | acceso embargado |
| Palabra clave: | Fisiologia de l'exercici Músculs Electromiografia Fatiga Estimulació elèctrica Exercise physiology Muscles Electromyography Fatigue Electric stimulation |
| Sumario: | [eng] The primary aim of this thesis was to compare the mechanisms underlying performance fatigability between males and females following a maximal intermittent fatiguing protocol (IFPmax), consisting of repeated half-squats performed with a flywheel device (FD). The body of the thesis comprises four consecutive studies: Study I examined sex differences in the effects of varying the moment of inertia on the within-session and between-session reliability of performance-related variables during the FD half-squat exercise. Measures derived from the FD half-squat demonstrate good reliability for assessing neuromuscular performance, with improved consistency observed at higher inertial loads, particularly in females. Moreover, the greater between-session variability observed in males suggests that more than one familiarization session may be necessary. Study II investigated the influence of sex on changes in kinetic and kinematic variables throughout the entire IFPmax. The results showed a progressive decline in performance variables, particularly during the second half of the protocol. When analyzing absolute values, males exhibited an earlier performance decrement compared to females. However, when normalized to body mass, performance decline was similar between sexes. Notably, peak and mean power emerged as the most sensitive variables for detecting fatigue. Study III explored sex differences in voluntary muscle activity patterns of the primary muscles involved in the task, by comparing set 1 and set 10 of the IFPmax. The reduction in performance was accompanied by decreased electromyographic (EMG) activity in the vastus lateralis and vastus medialis. Additionally, an increase in the hip-to-knee EMG ratio was observed in both sexes, although the underlying strategies appeared to differ. Males exhibited a marked reduction in knee extensor activity, whereas females showed a compensatory increase in hip extensor activity. While sex differences in agonist activity were partially influenced by initial performance output, this was not the case for antagonist muscles, suggesting the presence of sex-specific recruitment strategies. Study IV assessed sex differences in changes in force production and EMG responses derived from voluntary and electrically evoked responses immediately and 10 minutes after the IFPmax. The findings indicate a more pronounced impairment of contractile mechanisms compared to central mechanisms, with no recovery observed at 10 minutes. Notably, the comparable decline in central mechanisms between sexes immediately post-IFPmax points to a greater peripheral contribution to fatigability in males. However, when accounting for initial mechanical output, the observed sex differences were no longer statistically significant. |
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