Mental Fatigue Impairs Motor Performance but Not Motor Learning in Fatigued or Non-Fatigued Conditions

We investigated the influence of mental fatigue on motor performance and learning. Additionally, we examined whether practicing under mental fatigue induces resilience in future performance under similar fatigue conditions. Ninety-two participants were randomly assigned to a Mental Fatigue group (MENTAL-FATIGUE) or a Control group (CONTROL). The MENTAL-FATIGUE group completed a 30-minute Stroop task before practice, while the CONTROL group watched a movie. All participants practiced a Visuomotor Tracking Task (VTT). The experiment occurred over three days. On Day 1, participants completed a pretest (1 block of 5 trials), followed by their respective fatigue protocols, then practiced the VTT over 10 blocks. A post-test (1 block) followed the practice. On Day 2, participants performed a retention test under non-fatigued conditions. On Day 3, all participants completed the Stroop task and performed a fatigued retention test. Mental fatigue levels were assessed using a Visual Analog Scale before and after the fatigue protocols and at the end of Day 1. Motor performance was evaluated through the mean and variability of coincidence timing in the VTT. Results showed that mental fatigue impaired motor performance during acquisition but did not affect motor learning. Practicing under fatigue did not enhance future performance under similar conditions.