Movement-induced changes in body-specific attention are associated with perceived motor fatigue

Body-specific attention is a covert, body-centered attentional process that preferentially facilitates the processing of stimuli presented on one's own body. Although body-specific attention is associated with motor function and body use, whether it changes immediately following voluntary movement remains unclear. This study investigated whether voluntary hand movements immediately modify hand-related body-specific attention and whether perceived motor fatigue is associated with this change. Nineteen healthy adults performed repetitive left wrist flexion-extension movements. Body-specific attention and perceived motor fatigue were assessed before and after movement. Body-specific attention was quantified using a visual detection task as the reaction-time difference between stimuli presented on the participant's real and dummy hands. Perceived motor fatigue was assessed using an 11-point scale. No significant overall change in body-specific attention was observed after movement. However, changes in perceived motor fatigue were negatively correlated with changes in body-specific attention (Spearman's r = - 0.568, p = 0.011), indicating that greater increases in perceived motor fatigue were associated with a more negative change in body-specific attention. Exploratory analysis showed that body-specific attention increased after movement in participants without increased perceived motor fatigue, whereas this pattern was not observed in those reporting increased fatigue (time × group interaction: F₁,₁₇ = 7.173, p = 0.016, η²p = 0.297). Voluntary movement also induced an ipsilateral spatial attentional shift unrelated to perceived motor fatigue. These findings suggest that movement-related modulation of body-specific attention is associated with perceived motor fatigue.