Including Eye Movement in the Assessment of Physical Fatigue Under Different Loading Types and Road Slopes.

Area of Science:

• Occupational Health
• Human Factors Engineering
• Biomedical Engineering

Background:

• Emergency rescuers face high risks of musculoskeletal disorders due to prolonged heavy equipment carrying.
• Assessing physical fatigue under varied loading types and road slopes is crucial but currently limited.

Purpose of the Study:

• To investigate physical fatigue using electromyography (EMG) and eye movement metrics under different loading and slope conditions.
• To explore eye movement metrics as a novel, non-contact method for fatigue assessment.

Main Methods:

• Simulated prolonged load-bearing walking with 18 male participants.
• Experimental trials included four loading types and three road slope conditions.
• Collected data on EMG activity, eye movement metrics (saccade time, speed, amplitude, pupil diameter), and subjective fatigue ratings.

Main Results:

• Loading type and road slope significantly impacted EMG, eye movements, and perceived fatigue.
• Saccade metrics (time, speed, amplitude) strongly correlated with subjective fatigue and changed significantly across fatigue stages.
• Eye movement metrics, integrated into regression models, quantified physical fatigue under varied conditions.

Conclusions:

• Eye movement metrics show potential as non-invasive indicators for multidimensional fatigue monitoring.
• This research provides a new approach for assessing physical fatigue in occupational settings with dynamic physical demands.