Neuromuscular fatigue, cardiorespiratory, and perceptual responses are dependent on the amount of active muscle mass during exhaustive ramp incremental cycling
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2021-09
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Abstract
Exercise tolerance is determined by an integration of neuromuscular (NM), cardiorespiratory, and perceptual responses, the contributions and components of which differ according to the amount of muscle mass engaged in the exercise task. The present thesis aimed to utilize an exhaustive single- (SL) and double-leg (DL) ramp incremental cycling model to assess the effect of active muscle mass on NM fatigue and recovery kinetics alongside cardiorespiratory and perceptual responses. Twelve recreationally active males (age: 30 ± 5 years) performed counterweighted SL and DL ramp incremental cycling exercises to task failure. Central and peripheral fatigue were assessed at baseline, task failure, and 1, 4, and 8 min of recovery. Cardiorespiratory and perceptual responses were measured throughout the cycling tasks. The results from this study demonstrated that with similar exercise durations, maximal voluntary force and peripheral fatigue of the knee extensors declined more following SL cycling, along with increased perceived effort and leg pain. On the other hand, higher cardiorespiratory responses and dyspnea were evoked during DL cycling. Central fatigue and NM fatigue recovery did not largely differ between tasks. These findings suggest that the interplay between NM, cardiorespiratory, and perceptual determinants of exercise tolerance during incremental cycling to task failure is muscle mass-dependent. More specifically, while metabolic perturbations within working locomotor muscles (i.e., reflected in peripheral fatigue and muscle pain) are not the primary limiting factors during larger muscle mass exercise, they may instead play a primary role in modulating smaller muscle mass exercise tolerance. The present thesis may have implications on utilizing smaller muscle mass exercise in clinical and performance settings to enhance peripheral adaptations.
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Zhang, M. Y. (2021). Neuromuscular fatigue, cardiorespiratory, and perceptual responses are dependent on the amount of active muscle mass during exhaustive ramp incremental cycling (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.