Examining Central Fatigue Pathways under Stress: Integrating Insights from Graph Theoretical Neural Modeling and Motor Cortex Excitability

Abstract

Acute cognitive stress affects neuromuscular fatigue, but the underlying mechanisms are not well understood. The aim of this study was to identify the influence of stress on central fatigue and associated functional changes in the brain. Thirty participants, balanced by sex, performed intermittent elbow flexion contractions at 30% of their maximum strength till voluntary fatigue. Endurance time, strength loss, and voluntary activation loss rate were collected. Functional hemodynamic changes in the participants’ prefrontal and motor areas of the brain were also collected and used to calculate functional integration and segregation in the PFC and M1. Results show that stress had a facilitative effect on fatigability and the fatigue related decline in the functional integration and segregation of prefrontal cortex were not observed under stress. These findings demonstrate how the imposition of dual task demands in the workplace delays the perception of neuromuscular fatigue, thereby increasing the risk of injury.