Sex-specific Neural Strategies During Fatiguing Work in Older Adults

Area of Science:

• Neuroscience
• Ergonomics
• Human Factors

Background:

• Ergonomics studies historically lack diversity, potentially biasing results.
• Traditional "neck down" measurements miss nuanced sex differences in fatigue.
• A neuroergonomics approach, studying brain-behavior links during fatigue, offers unique insights.

Purpose of the Study:

• To investigate supraspinal (brain-based) mechanisms of exercise performance during fatigue.
• To determine if sex differences exist in these fatigue mechanisms.

Main Methods:

• Fifty-nine older adults performed fatiguing handgrip contractions.
• Measured traditional ergonomics outcomes (force variability, EMG, strength, endurance).
• Recorded prefrontal and motor cortex hemodynamic responses using neuroimaging.

Main Results:

• No significant sex differences in traditional fatigability outcomes or overall brain activation.
• Effective connectivity between prefrontal and motor areas was present in both sexes.
• Males exhibited higher interregional connectivity during fatigue compared to females.

Conclusions:

• Older males and females employ distinct sex-specific neuromotor strategies to maintain performance under fatigue.
• These brain-based adaptations, not evident in traditional metrics, highlight differing information flow between frontal-motor regions.
• Findings inform the development of targeted ergonomic strategies for diverse older adult populations.