Introduction Decreased balance ability may increase injury risk. Also, acute physical fatigue (APF) affects balance performance. Recently, reactive balance tasks were developed to assess balance in a more sport related context. Furthermore, it is unknown if APF induces changes in brain activity during different balance tasks. Therefore, the aim was to study whether (1) APF fatigue alters brain activity during one predefined and one reactive balance task, and (2) performance on these balance tasks.

Materials and Methods Twenty healthy participants volunteered for this cross-over study. APF was induced through a 30-second modified Wingate-protocol. Brain activity was measured through electroencephalography during both balance tasks and computed by means of spectral power analysis. The predefined balance task was the Y-balance test (YBT), while the neurocognitive balance test encompassed the reactive balance test (RBT).

Results Decreased RBT accuracy was observed after APF (p < 0.05), yet YBT performance and RBT visuomotor reaction time remained unaffected. APF induced α- and β-spectral power increments in the prefrontal, motor and posterior parietal cortex during YBT performance (p < 0.05). For the RBT, an α-spectral power increment in the posterior parietal cortex and a β-spectral power increment in the prefrontal cortex were observed due to APF (p < 0.05).

Conclusions APF induces different changes in brain activity during both balance tasks. It is likely that different central mechanisms are affected depending on the type of balance task. Further research is needed in an applied setting to gain insight in the possible interaction between APF and injury occurrence.