Mental fatigue impairs repeated sprint and jump performance in team sport athletes.

OBJECTIVES: We tested whether mental fatigue (MF), induced by a cognitively-demanding task, would impair repeated sprint ability (RSA) and repeated jump ability (RJA) performance, and whether physical fatigue and MF would impair psychomotor vigilance. DESIGN: Randomized within-participant design. METHODS: After establishing baseline peak countermovement jump (CMJ), 18 male participants performed 12 maximal 20-m (10-m linear + 10-m directional) repeated sprints (RSA random test) followed by 12 maximal repeated CMJs (RJA test) subsequent to 30-min Stroop task (MF) or a documentary (Control). Peak and mean running time and height, percent decrement score (Sdec), blood lactate, heart rate and RPE were measured for CMJ, RSA, and RJA tests. MF (M-VAS) and psychomotor vigilance [psychomotor vigilance test (PVT)] were measured at baseline, after each condition, and after the RSA/RJA tests. RESULTS: Compared to Control, the Stroop task elevated MF (p = .001), RPE ratings (all p < .031), and mean and Sdec performance in directional (but not linear) RSA (all p < .032) and RJA tests (all p < .034). PVT score worsened after Stroop task (p = .011) but not Control, declined after RSA/RJA tests in both conditions (all p < .023) and was lower in the MF condition (p = .029). No condition differences were noted for peak (CMJ, RSA and RJA tests) performance, blood lactate, and heart rate. CONCLUSIONS: MF impairs directional RSA, and RJA performance. This impairment was linked with increased RPE and without physiological changes. The progressive impairment in PVT score suggests a cumulatively negative effect of mental and physical fatigue on psychomotor vigilance.