International Archives of Occupational and Environmental Health

, Volume 67, Issue 1, pp 11–18

A case-control study of trapezius muscle activity in office and manual workers with shoulder and neck pain and symptom-free controls

  • O. VasseljenJr.
  • R. H. Westgaard
Original Article

DOI: 10.1007/BF00383127

Cite this article as:
Vasseljen, O. & Westgaard, R.H. Int. Arch Occup Environ Heath (1995) 67: 11. doi:10.1007/BF00383127


A case-control study with matched pairs was initiated to investigate the relationship between shoulder-neck complaints and activity in the upper trapezius muscle. The matching was done so that the physical demands from work (external exposure) were equal for both the case and the control. Each pair was also matched for gender, age, working hours, and employment time. Male (n = 18) and female workers (n = 78) employed in both manual and office work were included. Muscle activation levels and pause patterns during work and muscle activity during tests of attention, coordination, and rest were recorded by surface electromyography. The results showed consistent associations between pain and signs of increased activation of the upper trapezius for the cases in the manual group. No such associations were observed in the office group. The results are consistent with the hypothesis that muscle activation patterns may in some instances, but not in all, explain why some workers develop pain while others do not in work situations where the physical demands are similar.

Key words

ElectromyographyTrapeziusShoulder and neck painMyalgiaWork

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • O. VasseljenJr.
    • 1
  • R. H. Westgaard
    • 1
  1. 1.Division of Organization and Work Science, The Norwegian Institute of TechnologyThe University of TrondheimTrondheimNorway