Mental fatigue in elite sport

Mental fatigue has rapidly gained scientific attention in the physical performance domain. Whilst laboratory-based evidence has demonstrated the potential for mental fatigue to impair endurance performance in exercise and some sport-specific tasks, a lack of research has explored how elite athletes experience mental fatigue in the applied setting. Advancing the understanding of athlete mental fatigue is important to improve monitoring and management of the phenomena, ultimately aiding in maximisation of performance. This thesis compromises a series of independent but related studies which explore mental fatigue in the applied sporting environment.Initially a review of literature (Chapter 2) was performed to obtain a broad understanding of the impact of mental fatigue on physical performance, introduce potential theoretical mechanisms, and critically review previous research. From this extensive review, a refined narrative review (Appendix 5) was written to clearly address the application of mental fatigue research to elite team sport. The findings confirmed that mental fatigue has the potential to negatively influence sporting performance not only via deterioration in physical performance, but through changes in technique, decision-making and tactical and skill execution. The review emphasised that the majority of previous research was limited in its applicability and transferability to elite athlete performance. Highlighting the need for research to explore mental fatigue in athletic populations and establish evidence-based practical recommendations.Study 1 (Chapter 3) used a qualitative approach to investigate athlete and sport staff understanding of mental fatigue in elite sport. The main findings revealed athletes and staff believe mental fatigue negatively impacts sporting performance. Further, sport specific; descriptors and symptoms, perceived causes, and the temporal nature of mental fatigue in elite sport were identified. The findings informed future studies and improved understanding of how to monitor and manage mental fatigue in applied practice.Study 2 (Chapter 4) sought to quantify the presence of acute mental fatigue in the competitive environment. The novel findings revealed that both perceived mental and physical fatigue were found to increase across netball matches in elite development athletes. Subsequently, informing that whilst highly-trained individuals may display an increased resistance to mental fatigue, they are not able to avoid mental fatigue. The findings also indicated that athletes perceive mental and physical fatigue to differ in origin.Study 3 (Chapter 5) investigated mental fatigue throughout an elite netball pre-season. The novel findings established elite netballers to be susceptible to experiencing mental fatigue in the high-performance training environment. Ratings of mental fatigue and physical fatigue were found to fluctuate across the 16-week pre-season phase; with elevated ratings in the later pre-season weeks (i.e. as competition approached). The findings again supported mental fatigue and physical fatigue to be largely separate constructs longitudinally. Psychobiological stress was indicated by salivary markers of cortisol and alpha-amylase; however, neither emerged as a sensitive or robust biomarker of mental fatigue. A significant relationship was identified between increased ratings of mental fatigue and reduced readiness to perform. Athlete identification of the presence of mental fatigue and perceived relation to performance supports mental fatigue to be worthy of monitoring and management across a pre-season phase.Study 4 (Chapter 6) explored how elite athletes experience mental fatigue across a season and how mental fatigue relates to other common athlete-self report measures. A league wide approach captured daily athlete-self report measures from154 premier professional netballers across both the 2018 and 2019 seasons. When accounting for individual, mental fatigue fluctuated between rounds within a season; with higher ratings in round games towards the later part of the season. The findings indicated athletes perceive mental fatigue to differ from measures of physical fatigue, tiredness, stress, mood and motivation, however similarities were demonstrated with perceived sleep quality. The findings impress the need for practitioners to consider mental fatigue as an independent factor worthy of inclusion in athlete-self report measures and appropriately manage mental fatigue induced by the elite training and competition environment.Study 5 (Chapter 7) investigated whether mental fatigue of international representative netballers differed with varied contextual demands. The findings demonstrated an influence of contextual factors; with higher ratings reporting during training and preparation camps, comparative to competition. Within-group differences for individually identified subsets indicated athletes’ ratings of mental fatigue are likely responsive to a multitude of factors including; temporal or seasonal fluctuations, travel and environmental instability and selection. For the most-part perceived mental fatigue was relatively low, however the results showed that athletes competing at an international standard experienced elevated mental fatigue induced through the demands of elite sport training and competition.This thesis examined mental fatigue in the elite sporting environment. The methods incorporated qualitative, observational and longitudinal approaches to enhance the understanding of how athletes experience mental fatigue in an ecologically valid manner. The research advances previous findings by providing evidence which justifies the need for practitioners to be cognisant of appropriately monitoring and managing mental fatigue. Challenges in quantifying mental fatigue subjectively, objectively and physiologically, are highlighted and methodological approaches worthy of future investigation recommended.