Does experience mitigate the deleterious effect of mental fatigue on tactical performance? A study in youth soccer academies

The present study compared the effects of mental fatigue on the tactical performance of soccer players in the under-13, under-15, and under-17 categories. The sample of the present study comprised 70 elite male youth soccer athletes, including 23 under-13 players, 23 under-15 players, and 24 under-17 players. The athletes participated in small-sided games in a 3 vs. 3 format with goalkeepers under two conditions: experimental (presence of mental fatigue) and control (absence of mental fatigue). Mental fatigue was induced using an electronic version of the Stroop test for 20 min. Tactical performance was analysed through measures of interpersonal synchronization in the In-phase pattern, recorded by 10 Hz GPS units. The MANOVA revealed an interaction effect between Category*Condition (p = 0.003). It was observed that the under-15 category exhibited a significantly greater reduction than the under-17 category in the percentage of time in the In-phase synchronization pattern on the depth axis, both in the offensive (p < 0.001) and defensive phases (p < 0.001) during the experimental condition. Additionally, the under-15 category showed a significantly greater reduction than the under-13 category on the depth axis, both in the offensive (p < 0.001) and defensive phases (p < 0.001). In conclusion, athletes at more advanced developmental stages show greater resilience to mental fatigue in tactical performance, while younger players, such as those in the U-13 category, appear less affected—possibly due to the immaturity of their cognitive systems.