Temporal strategy and performance during a fatiguing short-cycle repetitive task.

Area of Science:

• Human Movement Science
• Occupational Ergonomics
• Fatigue Studies

Background:

• Sustained operator performance is crucial for industrial competitiveness.
• Repetitive tasks can lead to fatigue, impacting performance and safety.
• Understanding fatigue mechanisms in short-cycle work is essential for optimizing work environments.

Purpose of the Study:

• To investigate temporal changes in movement strategy and performance during fatiguing short-cycle work.
• To examine the relationship between movement strategy adaptation and physiological fatigue indicators.
• To identify potential strategies for mitigating fatigue and sustaining performance in repetitive tasks.

Main Methods:

• Eighteen participants performed repetitive reaching movements over six 7-minute work blocks.
• Electromyography (EMG) of the upper trapezius muscle was continuously recorded.
• Temporal movement strategy, timing errors, and perceived fatigue were assessed throughout the 1-hour study.

Main Results:

• Participants exhibited clear signs of fatigue, both subjectively and through EMG, within and across work blocks.
• Timing errors and waiting time at the target increased gradually.
• Adaptive changes in temporal movement strategy were negatively correlated with EMG level and variability, suggesting a compensatory mechanism.

Conclusions:

• An adaptive temporal movement strategy can offset the development of unstable motor solutions during fatiguing short-cycle work.
• Fatigue develops progressively within and across work blocks, impacting movement control.
• Industrial production should incorporate spatial and temporal flexibility to help operators counteract fatigue and sustain performance.