The Acute Effects of Maximal Fatigue on the Subsequent Performance of Endurance Trained Athletes

Abstract

Maximal stretch-shortening fatigue may have a detrimental effect on immediate performance of endurance-trained athletes, but once fatigue has subsided a potentiation effect may be evident. PURPOSE: The aim of this study was to investigate the acute effects of maximal stretch shortening cycle (SSC) fatigue on the subsequent performance of endurance trained athletes and to examine the pattern of recovery. METHODS: Nine endurance trained athletes performed four initial sets of drop and rebound jumps on sledge and force plate apparatus in order establish baseline levels of performance. A maximal SSC fatigue protocol was then performed by each subject; consisting of consecutive rebound jumps to a height of 90% of their maximum baseline jump until they could no longer reach their target on three consecutive jumps. This was followed immediately by one set of drop and rebound jumps at 15, 45, 120, 300 and 600 seconds post fatigue. Measurements of peak ground reaction force (GRF), ground contact time (CT), jump height, reactive strength index (RSI) and leg spring stiffness (kvert) were calculated for each drop jump (DJ) and rebound jump (RBJ). All recovery interval jumps were analysed and each subject's minimum and maximum post fatigue jump was selected for further analyses. A one-way ANOVA with repeated measures was used to evaluate the differences between the average of the baseline scores and the minimum and maximum scores achieved in the post tests. RESULTS: The fatigue protocol resulted in a significant reduction in jump height (p<0.001) and RSI (p<0.01) in the DJ and a significant reduction in GRF (p<0.01), jump height (p<0.01) and RSI (p<0.01) in the RBJ. The maximal fatigue workout also resulted in performance potentiation. During the latter recovery intervals, after fatigue had subsided, there was a significant improvement in performance in kvert (p<0.05) in the DJ and in GRF (p<0.001) and kvert (p<05) in the RBJ. This response was individual for each subject and occurred at either 300 or 600 seconds post fatigue. CONCLUSIONS: Exhausting SSC exercise induces a clear and immediate decrease in jumping performance and the biomechanical process of the jumps in endurance trained athletes. However, maximal SSC fatigue can also result in a potentiation affect in endurance athletes, in the latter stages of recovery. Funded by IRCSET