European Journal of Applied Physiology

, Volume 101, Issue 4, pp 445–456 | Cite as

The influence of body posture, arm movement, and work stress on trapezius activity during computer work

Original Article

Abstract

The study aimed to determine the influence of arm posture and movement on trapezius activity of computer workers, considering the full workday. A second aim was to investigate if work periods perceived as stressful were associated with elevated or more sustained muscle activity pattern. Twenty-six computer workers performing call-center (n = 11), help desk (n = 7), or secretarial (n = 8) work tasks participated. Bilateral trapezius surface electromyographic (sEMG) activity and heart rate was recorded throughout the workday. Simultaneous inclinometer recordings from left thigh and upper arms identified periods with sitting, standing, and walking, as well as arm posture and movement. Perceived work stress and tension were recorded on visual analog scales (VAS) every hour. Trapezius sEMG activity was low in seated posture [group median 1.8 and 0.9% of activity at maximal voluntary contraction (%EMGmax) for dominant and non-dominant side] and was elevated in standing (3.0 and 2.5% EMGmax) and walking (3.9 and 3.4% EMGmax). In seated posture (mean duration 79% of workday) arm movement consistently influenced trapezius activity, accounting for ∼20% of intra-individual variation in trapezius activity. Arm elevation was on average not associated with trapezius activity when seated; however, considerable individual variation was observed. There was no indication of increase in trapezius activity or more sustained activity pattern, nor in heart rate, in high-stress versus low-stress periods, comparing periods with seated posture for the subjects reporting contrasts of at least two VAS units in stress (n = 16) or tension (n = 14) score.

Keywords

Electromyography Trapezius Shoulder and neck pain Computer work Posture Work stress 

Notes

Acknowledgements

This study was supported by the Norwegian Research Council.

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Copyright information

© Springer-Verlag 2007

Authors and Affiliations

  1. 1.Department of Industrial Economics and Technology ManagementNorwegian University of Science and TechnologyTrondheimNorway
  2. 2.Human Movement Science Programme, Faculty of Social Sciences and Technology ManagementNorwegian University of Science and TechnologyTrondheimNorway

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