Mental fatigue changes from regular season to play-offs in semiprofessional soccer: A comparison by trainings days.

The main purpose was to compare by each training the mental load and fatigue reported by semi-professional soccer players comparing between regular season-phase and the play-offs. 53 players (M age =24.59 years) for two teams participated during the 2020/21 season. Mental load was measured with a Likert questionnaire. Mental fatigue was quantified with a Visual Analogue Scale. Four trainings were recorded each week (Monday=MD+1, Wednesday=MD-4, Thursday=MD-3 and Saturday=MD-1), with a competitive match on Sunday across 10-weeks (five dates of regular season - five dates of play-offs). A Linear Mixed Model was performed with R-studio, using the training days and the competitive phase as independent variables. The influence of time played as co-variable was also checked. Results showed MD+1 as the more mentally fatiguing day in both phases, although MD-4 were the training with higher mental load reported (p = .001). Comparing phases, mental fatigue was significantly higher during the play-offs (p = .037). With regard time played, players that did not usually play showed a decrease in mental load during the play-off´s. Then, we recommend coaches to use recovery strategies for mental fatigue, avoid mentally fatiguing tasks close to competition and considerer the time played as a factor which may contribute to individual differences in player mental fatigue.