Background Physical fatigue is known to decrease an athlete’s functional test performance (FPT), but less is known about the impact on the injury risk profile. Furthermore, adaptability and neurocognitive performance tests have been put forward as relevant concepts within injury prevention, but to date it is not known if acute peripheral fatigue affects functional and neurocognitive performance tests.

Objective To assess the impact of acute peripheral fatigue on lower extremity functional and neurocognitive tests.

Design Randomized counterbalanced cross-over design.

Setting Primary prevention clinical setting.

Participants Twenty healthy participants (three females and ten males; age=24±3 years; height=177.5±6.6 cm; weight=73.2±11.3 kg) participated in this study.

Interventions Acute peripheral fatigue was induced by a 30 second modified Wingate protocol matched for maximal 30 second power output, while the participants were seated on the bike for 30 seconds during the control task.

Main Outcome Measurements The Y-balance test (YBT), reactive balance test (RBT), single leg hop test (SLH) and countermovement jump (CMJ) were evaluated pre-post intervention.

Results ANOVA revealed no interaction effect of time and condition for the YBT. The CMJ & SLH were significantly lower post physical fatigue intervention (p<0.001), together with the SLH being significantly lower compared to control (p=0.027) post fatigue intervention. A significant decrease in RBT accuracy was observed post physical fatigue (p=0.004), with participants performing significantly worse when peripherally fatigued compared to control (p < 0.001). No differences were observed when considering the effect of acute peripheral fatigue on visuomotor reaction time in the RBT.

Conclusions In a fatigued state, accuracy in response to environmental stimuli decreases, while visuomotor reaction time remains unaffected. SLH and CMJ are also negatively affected by acute peripheral fatigue, although the functional test performance is not primarily determined by peripheral intra-muscular energy resources. Clinicians should consider evaluating injury risk in a fatigued state, together with the evaluation of neurocognitive performance tests.