MENTAL FATIGUE AND SPORT‑SPECIFIC PSYCHOMOTOR PERFORMANCE: A SYSTEMATIC REVIEW

INTRODUCTION:Mental fatigue (MF) is a psychobiological state that arises during prolonged demanding cognitive activity and results in an acute feeling of tiredness and/or a decreased performance capacity[1]. Research shows that MF negatively influences both cognitive (e.g. attention) and physical (e.g. endurance) performance[1]. Recently, multiple studies have indicated that MF could also impair sport-specific psychomotor performance[2] (SSPP; i.e. highly complex motor behaviour that results from the cognitive processing of sensory and perceptual information in a sport-specific context). SSPP encompasses outcomes such as reaction time and accuracy, which are important predictors ofperformance in a variety of sports. Nevertheless, a systematic overview detailing the effects of MF on SSPP is currently lacking.METHODS:PubMed (MEDLINE), Web of Science, PsycINFO and SPORTDiscus were searched (5th of November 2020). Studies were eligible when study outcomes encompassed any form of SSPP skill, the intervention was targeted to induce MF, and the population included healthy individuals. The presence of a manipulation check, to indicate the successful induction of MF, was obligatory for inclusion. Secondary outcomes were all outcomes (either physiological or psychological) that could explain the underlying mechanisms of the effect of MF on SSPP.RESULTS:In total, 21 papers were included. MF was successfully induced in all but two studies, which were excluded from further analysis. 17 out of the 19 analysed studies displayed a negative effect of MF on a myriad of SSPP outcome types, including decision-making, reaction time and accuracy. No changes in physiological outcomes, that could underlie the effect of MF, were reported. Subjectively, only ratings of perceived of exertion (RPE) increased due to MF in some studies.CONCLUSION:Overall, it is clear that MF can impact important aspects of SSPP, which is especially important for coaches employed in sports where SSPP determines a large part of total athletes’ performance. This systematic review enables the relevant stakeholders to make better decisions about which performance outcomes to monitor in relation to MF and potentially counter MF.Most secondary outcomes remained uninfluenced due to MF. Only RPE changed, which could be connected to adenosine accumulation in the brain, raising the perceived effort of the physical task and negatively influencing performance. However, these suggestions have been made before, and a clear confirmation of this theory using objective brain measurements is still lacking. Therefore, the brain should be the main focus of future studies to finally understand the effect of MF on human performance.1. Van Cutsem J, et al. The effects of mental fatigue on physical performance: A systematic review. Sports Medicine. 2017;47(8):1569-88.2. Russell S, et al. The application of mental fatigue research to elite team sport performance: New perspectives. Journal of Science andMedicine in Sport. 2019;22(6):723-8