Comparação entre o comportamento da fadiga central e periférica no domínio extremo e severo de exercício

Abstract

The reduction in muscle performance during an exercise can be attributed to central or peripheral fatigue. Studies have determined the origin of fatigue in three exercise-intensity domains: moderate, heavy and severe. However, there is no scientific evidence indicating the mechanism of fatigue in the extremeintensity domain. This study investigated the fatigue development after the extreme-intensity domain in comparison to the severe-intensity domain. Nine women performed: Day 1 – a maximal incremental; Day 2 – a familiarization test; Day 3, 4 and 5 – three constant-load exercise trials to determine critical power; Day 6 and 7 – experimental trials, one in the severe-intensity domain (10% above critical power) and another one in the extreme-intensity domain (140% of maximal power output obtained in the incremental test). Neuromuscular function was assessed before and immediately after each trial. There was no alteration in voluntary activation (p> 0.05) post-exercise in both domains. The MVC decreased after exercise (p=0.001) in both exercise domains, indicating global fatigue for both. The peripheral markers Qtw10 and Qtw100 significantly reduced after both exercise domains (p= 0.001). In conclusion, the exercise performed in the extreme domain presented the same model of fatigue found in exercises in the severe domain, that is, no central fatigue and only peripheral fatigue.