Mendez-Villanueva, A., Hamer, P., & Bishop, D. (2007). Fatigue responses during repeated sprints matched for initial mechanical output. Medicine and Science in Sports and Exercise, 39, 2219-2225.

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This study compared muscle fatigability during two sets of repeated cycling sprints matched for initial mechanical output in nonfatigued and fatigued states. Young men (N = 8) performed 10, 6-second all-out sprints on a cycle ergometer interspersed with 30 seconds of recovery. After six minutes of passive recovery, five 6-second sprints, again interspersed by 30 seconds of recovery were performed.

Total work was similar in sprints 4 and 11. The decrease in total work for sprints 4 through 8 was significantly less than the decrease for sprints 11 through 15. Despite no significant differences in total work values achieved in sprints 4 and 11, the amplitude of the electromyogram recorded during sprint 11 was 12.0% lower than in sprint 4. In contrast, values of the electromyogram median frequency recorded during sprints 4 and 11 were similar. The rate of decrease in electromyogram activity was similar for the two set of sprints.

Implication. A fatiguing repeated-sprint exercise, followed by a rest period, induces greater fatigability during subsequent repeated-sprint exercise regardless of the initial mechanical output. Fatigue changes are associated with acute neuromuscular adjustments.

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