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Updated: May 26, 2026
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Using Facial Electromyography to Assess Facial Muscle Reactions to Experienced and Observed Affective Touch in Humans
Published on: March 15, 2019
Evidence for repetitive load in the trapezius muscle during a tapping task
L Tomatis1, C Müller, M Nakaseko
1Institute of Human Movement Sciences and Sport, Swiss Federal Institute of Technology, Zurich, Switzerland. tomatisl@ethz.ch
European Journal of Applied Physiology
|December 24, 2011
Summary
The upper trapezius muscle is phasically active during key tapping, showing significant correlation with forearm muscle activity. This dynamic activation pattern is consistent regardless of key characteristics.
Area of Science:
- Biomechanics
- Neuroscience
- Ergonomics
Background:
- Repetitive key-tapping studies often focus on continuous muscle activation.
- The phasic activation of the upper trapezius during supported key tapping remains less understood.
Purpose of the Study:
- To investigate phasic upper trapezius muscle activity during supported key tapping.
- To determine the cross-correlation between trapezius and forearm muscle activity.
- To assess if trapezius activity is influenced by key characteristics.
Main Methods:
- Surface electromyography (EMG) recorded trapezius, finger extensor, and flexor muscle activity.
- Key on-off signals were captured during a 4 Hz, 2-minute key-tapping task.
- Time-normalized EMG envelopes were analyzed using effect size and cross-correlation analyses.
Main Results:
- A phasic burst of upper trapezius muscle activation was observed in most key-tapping cycles (effect size ≥0.5 in 67% of subjects).
- High cross-correlation coefficients (0.75–0.98) were found between trapezius and forearm muscle activity.
- Trapezius muscle activation patterns were independent of specific key characteristics.
Conclusions:
- The upper trapezius muscle exhibits dynamic, phasic activity during repetitive key tapping.
- This trapezius muscle activity is strongly correlated with forearm muscle activation.
- Key characteristics do not appear to modulate the observed trapezius muscle activation patterns.
