Physical and cognitive contributions to fatigue perception: The interplay between local muscle fatigue and sensory prediction error.

Fatigue perception during exercise arises from complex body-brain interactions, but integration of local muscle fatigue with sensory prediction errors remains unclear. Traditional cognitive frameworks overlook dynamic physiological contributions. This study examined how local muscle fatigue and prediction errors jointly shape fatigue perception across spatial-temporal domains. Two experiments used naturalistic running with physiological monitoring, inducing temporal and spatial prediction errors by manipulating performance feedback. Computational models quantified contributions of muscle fatigue, prediction errors, and their interactions. Results showed fatigue perception is driven by both muscle fatigue and prediction errors, with domain-specific interactions: temporal errors linearly amplified muscle fatigue's impact, while spatial errors modulated it exponentially. These findings challenge purely cognitive models, demonstrating that fatigue perception emerges from domain-dependent integration of physiological signals and sensory discrepancies. The study provides a unified computational framework for body-brain interactions in fatigue, offering insights for personalized training and rehabilitation targeting both physical and cognitive fatigue pathways.