Effects of isolated locomotor muscle fatigue on pacing and time trial performance

H.M. de Morree, S.M. Marcora

Research output: Contribution to journalArticleScientificpeer-review

30 Citations (Scopus)

Abstract

Purpose
Locomotor muscle fatigue impairs exercise performance during time to exhaustion tests. However, its effect on self-regulation of power output (pacing) is unknown. The primary aim of this study was to investigate the effects of locomotor muscle fatigue on pacing and time trial performance.
Methods
Ten healthy recreationally active men completed a 15-min time trial on a cycle ergometer 30 min after undergoing an eccentric fatiguing protocol designed to induce a substantial strength loss in the knee extensor muscles without inducing significant metabolic stress. This fatigue condition was compared with a control condition, using a randomly counterbalanced AB/BA crossover design.
Results
Total work completed during the 15-min cycling time trial was significantly reduced by 4.8 % in the fatigue condition compared with the control condition. This was caused by a significant reduction in power output. Rating of perceived exertion was significantly higher in the fatigue condition compared with the control condition only during the first 3 min of the time trial. Heart rate and vastus lateralis integrated electromyogram were not significantly different between the two conditions.
Conclusion
The results show that participants with fatigued locomotor muscles reduce their pace but do not change their pacing strategy. As a result, there was a significant reduction in time trial performance. As predicted by the psychobiological model of exercise performance, a slower pace may be a behavioral response to compensate for the significant increase in perception of effort induced by locomotor muscle fatigue.
Keywords: Perception of effort, Cycling exercise, Eccentric fatigue, Pacing strategy, Exercise tolerance, Electromyography
Original languageEnglish
Pages (from-to)2371-2380
JournalEuropean Journal of Applied Physiology
Volume113
Issue number9
DOIs
Publication statusPublished - 2013

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