Mental fatigue is a psychobiological state caused by prolonged periods of demanding cognitive activity shown to negatively influence physical performance. Variation exists across the literature regarding the manifestations and impact of mental fatigue; with little knowledge of the domain‐specific manifestations in elite sport. The difficulties in defining mental fatigue may explain why it is not consistently assessed by coaching or support staff. The aim of this study was therefore to investigate athlete and staff understandings of mental fatigue in elite sport. Nine focus group discussions were conducted involving a total of 32 athletes (n = 17) and staff (n = 15) from elite sporting organisations. Athletes and staff believe mental fatigue negatively impacts sporting performance. Analysis revealed perceived associations between mental fatigue and changes in behaviour including, disengagement, decreased motivation and enthusiasm, increased displays of emotion and withdrawal. Changes in concentration, decreased discipline and attention to detail also emerged as descriptors of mental fatigue. Media engagements, study and work commitments were reported to induce mental fatigue. Repetitive tasks, over‐analysis, thinking about the sport in question and environmental instability were further reported perceived causes. Experience and personality emerged as factors contributing to individual susceptibility. Mental fatigue is perceived to not only develop acutely but also build in a cumulative manner in the elite sporting environment. The present findings inform the design of future studies examining MF in elite athletes; they also hold the potential to improve how best to monitor and manage the condition in applied practice.

Purpose: Mental fatigue is emerging as an important consideration for elite sporting performance, yet it is rarely monitored. The present study assessed changes in mental fatigue in professional team-sport athletes across 2 seasons and examined the relationship between mental fatigue and other athlete self-report measures of well-being. Methods: Elite netballers contracted to all teams competing in Australia’s premier professional netball competition during the 2018 and 2019 seasons (N = 154) participated. Using 5-point Likert scales, mental fatigue, fatigue (physical), tiredness, sleep quality, stress, mood, and motivation were assessed daily across 2 seasons composed of 14 round and finals series. Results: The ratings of mental fatigue significantly changed during both seasons. In 2018, lower ratings of mental fatigue were reported in round 1 versus 3, 4, 6, 8, and 14; round 7 versus 6; and round 6 versus 10 (P < .05). In 2019, lower ratings of mental fatigue were identified for round 1 versus 3, 9, 10 to 14, and semifinal; round 2 versus 10 to 13; and 5 versus 10 to 12 (P < .05). Ordinal regression revealed significant differences between mental fatigue and physical fatigue (P < .001), tiredness (P < .001), stress (P < .001), mood (P < .001), and motivation (P < .05). Conclusions: The present study found mental fatigue to significantly fluctuate across a season in elite netballers. Moreover, perceived mental fatigue differed from physical fatigue, tiredness, stress, mood, and motivation. The data impress the need for mental fatigue to be included as an independent measure of athlete well-being. Monitoring of mental fatigue can allow practitioners to implement strategies to manage its influence on performance.

Mental fatigue has been shown to negatively influence physical, technical and tactical aspects of sporting performance. However, mental fatigue is not routinely monitored or managed in elite sport and it is not clear whether mental fatigue occurs and/or changes across the varied contextual demands experienced by elite athletes in training, preparation and competition. This study explored self‐report measures of mental fatigue across eight training camps and six competition periods (two benchmark tournaments and four international test series) with international netballers (n = 22, 25.9 ± 2.7 years) during the 2018–2019 representative period. Mental fatigue was higher during training camps (p < 0.001; 3.20 [3.12, 3.27]) and preparation camps (p < 0.05; 3.27 [3.19, 3.34]) compared to the competition periods (3.49 [3.44, 3.55]). Significant within‐group differences were also identified between individual preparation camps and competition subsets. Higher mental fatigue was reported during the preparation camp for international test series 2 comparative to the preparation camp for benchmark tournament 1 (p = 0.047). For individual competitions; greater mental fatigue was found during the international test series 3 competition in comparison to both the benchmark tournament 1 (p <0.001) and international test series 1 (p = 0.020) competition periods. International representative netballers experience differing levels of mental fatigue across training and preparation camps and competition periods. Practitioners should be aware that athletes report instances of elevated mental fatigue across camps, and competition. Mental fatigue is not limited to competition and thus is recommended to be monitored during periods of training and preparation for competition. Highlights: International representative netballers experience differing levels of mental fatigue across camp and competition environments. Mental fatigue was higher during training camps and preparation camps compared to the competition periods. Mental fatigue is not limited to competition so is recommended to be monitored during periods of training and preparation for competition.