We’ve all had a bad day in the gym or out on the field. Sometimes we can explain why, sometimes we can’t. Fatigue from lack of sleep for example, is a known contributor to increased reaction time. Additionally, soreness and residual fatigue from training can also compromise performance. This demonstrates the importance of attaining sufficient sleep and recovery to support optimal performance. However, what about the times when the usual suspects (i.e., lack of sleep or physical fatigue) are not the cause of poor performance? Is it possible that performance decrements may be attributable to mental fatigue? That is, can a high mental workload earlier in the day may negatively impact subsequent performance at practice or competition?
A new study published ahead of print in the Journal of Sport Sciences investigated the effects of mental fatigue on subsequent performance in 12 well-trained male soccer players. On two separate occasions separated by 72 hours, the soccer player performed a soccer-specific decision-making task. On one occasion (in random order), before the soccer performance test, the athletes performed the Stroop task. The Stroop task is a computer-based activity where the user is challenged to correctly read the name of a color when the color of the text is arbitrary. On the other occasion, the athletes were given a magazine to read for 30 minutes (control condition) prior to the soccer-specific decision-making task. Decision errors and reaction time were recorded for analysis.
The results showed that subjective ratings of mental fatigue and effort were almost certainly higher following the Stroop test. The athletes decision-making accuracy on the soccer-specific decision-making test was likely lower following the Stroop test. In addition, response-time was likely higher (i.e., slower responses) following the Stroop test. Therefore, it appears that mental fatigue has a substantial effect on subsequent sport-specific performance in athletes. Many coaches are already aware of this, and regularly quantify perceived stress levels in their athletes. This may be useful for adjusting workloads for players, particularly during times of known high stress, such as academic examinations.
Smith, M. R., Zeuwts, L., Lenoir, M., Hens, N., De Jong, L. M., & Coutts, A. J. (2016). Mental fatigue impairs soccer-specific decision-making skill. Journal of Sports Sciences, In Press.