Mental fatigue measured in real-world sport settings: a case study of world class beach volleyball players

This study aimed to investigate mental fatigue experienced by beach volleyball players during Brazilian Beach Volleyball Tournament. The perception of mental fatigue pre-to-post-match, and perception after a win or loss were compared. A secondary aim was to associate mental fatigue with technical-tactical efforts. Seven senior world class beach volleyball players participated. A total of 30 official matches was analyzed, and seven senior world class beach volleyball players participated. The data were collected throughout national Tournaments Elite Top 8, and a digital platform accessed by the athletes' smartphones was used. A digital visual analogic scale (VAS) anchored 0 – 100 was used to measure subjective mental fatigue and technical-tactical effort. A one way repeated measures ANOVA revealed a difference pre-to-post-match for perceived mental fatigue [F(1.82 29.26)= 6.152; p= 0.007; ɳρ2 = 0.278, large effect; power= 0.833] and cubic trend [F(1.00 16.00) = 19.677; p < 0.001; ɳρ2 = 0.552, large effect; power= 0.986]. Moreover, subjective mental fatigue was higher after losing an official match (Win: 54.14 ±23.24 Vs. Loss: 69.66 ±27.24; p = 0.064; ES = 0.639, moderate effect), and linear regression identified a relationship between subjective mental fatigue and technical-tactical effort (R2 = 0.47; p < 0.001). In conclusion, increased mental fatigue was observed in world class beach volleyball players after official matches, and losing a match seemed to augment this response. Moreover, 47% of variation in subjective mental fatigue after an official match was explained by technical-tactical effort. Therefore, athletes should avoid cognitive activities immediately prior to official matches. It is possible that resistance to mental fatigue is a contributor to success in an official beach volleyball match, but this requires further investigation.