נק' מוניטין:
58,702
Central Regulation and Neuromuscular Fatigue during Exercise of Different Durations.
Froyd C, et al. Med Sci Sports Exerc. 2016.
Abstract
PURPOSE: The aim of this study was to determine if exercise time trials (TT) of different durations would cause different levels of peripheral and central fatigue during exercise.
METHODS: Twelve trained subjects (11 men, 1 woman) performed TTs lasting 3, 10 and 40 min with repetitive self-paced concentric right knee extension at 60 deg[BULLET OPERATOR]s on an isokinetic dynamometer. Neuromuscular function was assessed prior to, during, and immediately after the TTs using voluntary and electrically evoked forces.
RESULTS: Maximal voluntary contraction (MVC) force, evoked peak force for single stimulus (SS), and rating of perceived exertion reached similar levels at termination of all TTs. Evoked peak force for paired stimuli of 100 Hz (PS100) decreased more for the 40-min compared to the 3-min TT (-42 ± 15% vs -37 ± 13%, P < 0.05) and central fatigue was significant for the 40-min and 10-min but not for the 3-min TT. SS and PS100 decreased while voluntary electromyography normalized to M-wave for self-paced contractions increased during the end-spurt in all TTs.
CONCLUSION: These data demonstrate that the extent of peripheral and central fatigue that contribute to reductions in force of single limb dynamic contractions depend on the duration and intensity of self-paced exercise. There was no evidence for a critical threshold in peripheral fatigue that was common to all time trials.
Froyd C, et al. Med Sci Sports Exerc. 2016.
Abstract
PURPOSE: The aim of this study was to determine if exercise time trials (TT) of different durations would cause different levels of peripheral and central fatigue during exercise.
METHODS: Twelve trained subjects (11 men, 1 woman) performed TTs lasting 3, 10 and 40 min with repetitive self-paced concentric right knee extension at 60 deg[BULLET OPERATOR]s on an isokinetic dynamometer. Neuromuscular function was assessed prior to, during, and immediately after the TTs using voluntary and electrically evoked forces.
RESULTS: Maximal voluntary contraction (MVC) force, evoked peak force for single stimulus (SS), and rating of perceived exertion reached similar levels at termination of all TTs. Evoked peak force for paired stimuli of 100 Hz (PS100) decreased more for the 40-min compared to the 3-min TT (-42 ± 15% vs -37 ± 13%, P < 0.05) and central fatigue was significant for the 40-min and 10-min but not for the 3-min TT. SS and PS100 decreased while voluntary electromyography normalized to M-wave for self-paced contractions increased during the end-spurt in all TTs.
CONCLUSION: These data demonstrate that the extent of peripheral and central fatigue that contribute to reductions in force of single limb dynamic contractions depend on the duration and intensity of self-paced exercise. There was no evidence for a critical threshold in peripheral fatigue that was common to all time trials.
