Functional And Psychological Responses To Acute Fatigue During Single-Leg Hop Testing In Young Professional Soccer Players

Abstract

Background: Fatigue has been recognized as a key factor influencing both physical performance and psychological readiness in athletes. However, limited evidence exists regarding its combined effect on single-leg hop performance and psychological readiness in soccer players.

Objective: To investigate the impact of induced fatigue on single-leg hop performance and psychological readiness to return to sport in professional male soccer players.

Methods: A total of 105 professional male soccer players underwent a fatigue protocol, and pre- and post-fatigue assessments included single-leg vertical jump, single-leg hop for distance and single-leg side hop test. Psychological readiness was assessed using the Anterior Cruciate Ligament–Return to Sport after Injury (ACL-RSI) scale. Paired t-tests compared pre- and post-fatigue outcomes, while Spearman’s rho examined correlations between fatigue index and outcomes.

Results: All hop performance measures significantly declined post-fatigue (p < 0.001), with large effect sizes (d = 1.08–1.18). Vertical jump height, power, and RSI-mod decreased, while contact time increased. Single-leg hop for distance and side hop tests also showed significant reductions. ACL-RSI scores decreased modestly post-fatigue (d = 0.19). The fatigue index correlated negatively with side hop performance on both limbs (Right: r = –0.204, p = 0.004; Left: r = –0.157, p = 0.028) and with ACL-RSI scores (r = –0.531, p = 0.034), but not with other performance measures.

Conclusion: Fatigue substantially impairs hop performance and moderately reduces psychological readiness in professional soccer players. The observed associations between fatigue, lateral hop ability, and psychological readiness highlight the importance of incorporating fatigue-based assessments into return-to-sport decision making.