Effects of Mental Fatigue on Agility,Explosive Strength of Low-limb and Balance in Soccer Players

Objective: Mental fatigue(MF) is a psychobiological state caused by prolonged periods of demanding cognitive activity and characterized by subjective feelings of “tiredness” and “lack of energy”. To clarify the effects of MF on different physical ability in soccer players has great significance for them to conduct training and competition. Therefore, the purpose of this study is to investigate the effects of mental fatigue on agility(AGT), explosive strength of low-limb(CMJ) and balance(YBT) in soccer players. Methods: 18 male amateur soccer players age:(20.72±2.42) yrs, height:(177.08±5.99) cm, body mass:(71.16±9.55) kg,body fat percentage: 16.3%±4.3%, training experience:(6.61± 3.91) yrs participated a randomized crossover trial, and were asked to finish both 45 min Stroop task(MF group) and 45 min emotionally neutral video watching task(control group) with an interval ≥48 h. After each task, participants were instructed to participated in three tests for agility, low-limb explosive strength and balance assessment. VAS-MF and VAS-MO pre-post treatment and RPE after each test were collected for analysis. Results: The values of VAS-MF at pre-treatment in MF group were similar to control group(P=0.281), while VAS-MF at post-treatment(P=0.002) and the changes of VAS-MF pre-and post-treatment in MF group(P=0.001) were all higher than control group. The values of VAS-MO at pre-treatment, post-treatment and the changes of VAS-MO in MF group were similar to control group(P=0.385, 0.288and 0.726). The differences of performance of AGT(t=0.764, P=0.455, d=0.18, 95% CI=-0.288~0.643), CMJ(t=0.116, P=0.909, d=-0.027, 95% CI=-0.489~0.435) and YBT(YBT-Left: t=0.547, P=0.591, d=0.129, 95% CI=-0.337~0.591; YBT-Right: t=1.078, P=0.296, d=0.254, 95% CI=-0.219~0.720) were not significant between MF group and control group. The differences of RPE of AGT(P=0.307), CMJ(P=0.083) and YBT(P=0.088) were not significant between MF group and control group. Conclusions:Mental fatigue doesn't impair agility, explosive strength of low-limb and balance performance in soccer players.