This recent study we published is very fundamental but imagine the clinical implications. We employ balance tasks for risk assessment, return-to-play decisions, and performance measures. Normally in non-fatigued conditions. But, did you know the outcomes of these test change when the subject is fatigued?
Background
While mental fatigue increases the probability of losing balance, the underlying neural mechanisms remain to be studied. Balance is commonly represented by technical outcomes difficult to translate to clinical practice. Therefore, the aims of this study were to assess how mental fatigue affects clinician-friendly balance tests and if mental fatigue interacts with brain activity during these tests.
Methods
Twelve healthy recreational athletes (age = 23 ± 2 years) participated. Mental fatigue was induced by a 90-minute Stroop test, while the control task encompassed a time-matched documentary. Two clinician-friendly balance tests (ie, Y-balance test [YBT], reactive balance test [RBT]) were performed before and after the 90-minute tasks. Brain activity was measured using electroencephalography during YBT and RBT.
Results
Mental fatigue significantly decreased RBT accuracy compared to pre-fatigue and compared to post-control. Mental fatigue did not affect YBT performance and visuomotor reaction time on the RBT. During the YBT, mental fatigue significantly induced higher prefrontal cortex theta activity. Brain activity during the RBT remained unchanged post-fatigue. Mental fatigue impairs RBT performance, but no underlying brain activity changes were observed. In contrast, YBT performance did not change due to mental fatigue, but alterations in brain activity during YBT performance were in line with previous mental fatigue research.
Perceived mental fatigue (M-VAS). *Significant difference between MF and CON (P < .05). ^Significant higher MF in POST-intervention compared to baseline, PRE-intervention, and follow-up (P ≤ .01). §Significantly higher MF in follow-up compared to baseline, and PRE- intervention. CON, Control group; MF, Mental Fatigue group
Mental fatigue can impair balance performance and alters electrophysiological brain activity during balance performance. Mental fatigue induced a higher prefrontal cortex theta activity during the Y-balance test, without affecting Y-balance performance. In contrast, accuracy in the reactive balance test decreased when mentally fatigued, but no alterations in brain activity or visuomotor response time were observed in response to mental fatigue. Future studies should further explore the potential underlying brain mechanisms that coincide with mental fatigue and interfere with both balance and neurocognitive performance.
The full article can be found here (paywalled)
Tassignon B, Verschueren J, De Pauw K, Roelands B, van Cutsem J, Verhagen E, Meeusen R. Mental fatigue impairs clinician-friendly balance test performance and brain activity. Transl Sports Med. 2020;00:1–10.