Active pauses induce more variable electromyographic pattern of the trapezius muscle activity during computer work

Area of Science:

• Ergonomics and Occupational Health
• Biomedical Engineering
• Musculoskeletal Research

Background:

• Repetitive computer mouse work can lead to muscle fatigue and disorders.
• Understanding trapezius muscle activity during computer tasks is crucial for prevention.
• Previous research indicates uneven muscle rest distribution in the trapezius.

Purpose of the Study:

• To evaluate the effects of active versus passive pauses on trapezius muscle activity.
• To investigate the distribution of trapezius surface electromyographic (SEMG) activity during computer mouse use.
• To explore how different work paces and pause types influence muscle engagement patterns.

Main Methods:

• Twelve healthy males participated in a laboratory study involving computer mouse work.
• Subjects performed 10-minute work sessions with passive (rest) or active (30% MVC shoulder elevation) pauses every 2 minutes.
• Surface electromyography (SEMG) was recorded from four regions of the trapezius muscle at low and high work paces.

Main Results:

• The upper trapezius muscle exhibited less relative rest time compared to the lower parts (p<0.01).
• Active pauses resulted in a lower centroid of exposure variation analysis (EVA) along the time axis compared to passive pauses (p<0.05).
• Active pauses promoted a more variable muscle activity pattern during computer work.

Conclusions:

• The findings confirm lower rest periods in the upper trapezius, consistent with clinical observations.
• Active pauses appear to enhance muscle activity variability, potentially mitigating risks of work-related musculoskeletal disorders.
• Implementing active pauses could be a beneficial ergonomic strategy for computer users.