The Effect of Mental Fatigue on Lower Limb Functional Performance Tests and Brain Activity in a Healthy Population

The Effect of Mental Fatigue on Lower Limb Functional Performance Tests and Brain Activity in a Healthy Population

The Influence of Acute Mental Fatigue on Functional Performance Tests of the Lower Limb and Brain Activity in a Healthy Population

Objective of the study The main objectives of this project are: To assess the influence of mental fatigue on a return-to-play test battery in healthy population To assess the influence of mental fatigue on brain functioning during a balance and reaction time task in healthy population In a later stage, these experiments could be carried out in a clinical context (e.g. in an ankle sprain population). The researchers will use a randomized, placebo controlled, counter-balanced, cross-over design. Thirteen healthy subjects will visit the lab 3 times. On the first visit (familiarisation trial), the investigators will collect the participants' characteristics. The participants will also be familiarized to the procedures and materials of the experiment during this first visit. The second and third visit contain the experimental setup and will proceed as follows: first, the participants will fill in a mental fatigue scale (M-VAS) and motivation scale. Next, the subjects will carry out a functional test battery (hop test, vertical jump test, Y-balance test, and a balance reaction-time test). Session rate of perceived exertion (RPE) is measured to indicate how fatigued the participants feel because of the test battery; also, M-VAS is collected once more. Then, a short cognitive task (Flanker task) is followed by either a long intensive cognitive task (90 minutes Stroop task) or control task (90 minutes documentary). Afterwards, participants have to carry out the Flanker task, fill in M-VAS (2x), perform the same test battery, fill in session RPE and one final fatigue scale (Nasa TLX). Heart frequency and EEG will be measured continuously during the trials.

Change in single-leg hop test for distance performance: from baseline and 120 minutes after baseline (immediately after the flanker task)

Change in vertical jump height performance: from baseline and 120 minutes after baseline (immediately after the flanker task)

Balance and reach performance; participants have to maintain their balance while reaching as far as possible along 3 different directions.

Change in Y-balance performance: from baseline and 120 minutes after baseline (immediately after the flanker task)

Balance and reaction time performance; participants have to maintain their balance while reacting as fast as possible in 3 different directions.

Change in balance and reaction time performance: from baseline and 120 minutes after baseline (immediately after the flanker task)

Brain activity during the Y-balance test, balance-reaction time test and flanker task will be registered at baseline and immediately after the flanker task

Change in EEG power spectrum: from baseline and 120 minutes after baseline (immediately after the flanker task)

Change in M-VAS: at baseline, 20 min after baseline (immediately after the first test battery), 120 min after baseline (immediately after the second flanker task) and 135 min after baseline (immediately after the final test battery)

Objective measure of mental fatigue; reaction time and accuracy give an objective indication of mental fatigue

Change in flanker task: at baseline and 90 minutes after baseline (immediately after the mental fatiguing task)

90 minutes mental fatiguing task; reaction time and accuracy give an objective indication of mental fatigue

Change in reaction time and accuracy will be assessed with a 90-min cognitive task; Reaction Time and Accuracy during the 90-min task will be reported as mean reaction time and accuracy during 8 blocks of 11min15sec

Inclusion Criteria: Healthy (No neurological/cardiorespiratory/psychological disorders) Male and female No medication Non-smoker Between 18 and 35 years old Exclusion Criteria: Back and/or lower extremity injuries during the past 6 months Bone/joint abnormalities Dizziness, history of loss of consciousness, any inner ear disorders Nervous system disorders or dysfunctions Uncorrected eye disorders/dysfunctions Illness Use of medication or any kind of drugs Use of alcohol, caffeine and heavy efforts 24 hours before each trial Not eating the same meal the night before and the morning of each trial