The present study used a neuroergonomic approach to examine the interaction of mental and physical fatigue by assessing prefrontal cortex activation during submaximal fatiguing handgrip exercises.

Mental fatigue is known to influence muscle function and motor performance, but its contribution to the development of voluntary physical fatigue is not well understood.

A total of 12 participants performed separate physical (control) and physical and mental fatigue (concurrent) conditions at 30% of their maximal handgrip strength until exhaustion. Functional near infrared spectroscopy was employed to measure prefrontal cortex activation, whereas electromyography and joint steadiness were used simultaneously to quantify muscular effort.

Compared to the control condition, blood oxygenation in the bilateral prefrontal cortex was significantly lower during submaximal fatiguing contractions associated with mental fatigue at exhaustion, despite comparable muscular responses.

The findings suggest that interference in the prefrontal cortex may influence motor output during tasks that require both physical and cognitive processing.

A neuroergonomic approach involving simultaneous monitoring of brain and body functions can provide critical information on fatigue development that may be overlooked during traditional fatigue assessments.