Central Fatigue in Repetitive Motor Tasks in the Temporal Domain

Abstract

Why and how do individuals experience fatigue when doing repetitive motor tasks, specifically with timing tasks such as musical rhythms? Previous research into motor fatigue involving tasks without large amounts of physical exertion supports the idea that fatigue is accrued by a breakdown of the surrounding muscles. However, a separate alternative theory of fatigue, the expected value of control theory, involves fatigue accruing from a perceived value of the task and of task-switching, and this has yet to be studied in the motor domain. Three groups of participants (N = 120 total, 40 each) performed a repetitive temporal rhythm-like finger tapping task for 8 minutes, then a 5-minute break, then two testing trials. The groups differed in engagement level of the stimuli presented, but had the same motor task. Results showed that within-trial fatigue was similar across groups but mostly negligent overall, with post-rest gains not presenting in a way consistent with fatigue buildup throughout the study. This is most likely due to the study being too short and not physically demanding enough for participants to experience fatigue as expected. Results also showed that participants increased vigor over time, which is also not consistent with expected fatigue. Future research needs to be conducted to induce more fatigue and be able to evaluate fatigue difference with engagement manipulation.