European Journal of Applied Physiology

, Volume 94, Issue 1, pp 158–167

A comparison of muscular activity during single and double mouse clicks

Authors

    • National Institute for Working Life
    • Department of Product and Production Development/Human Factors EngineeringChalmers University of Technology
  • Mikael Forsman
    • National Institute for Working Life
    • Department of Product and Production Development/Human Factors EngineeringChalmers University of Technology
  • Susan Hallbeck
    • Department of Industrial and Management Systems EngineeringUniversity of Nebraska
Original Article

DOI: 10.1007/s00421-004-1312-1

Cite this article as:
Thorn, S., Forsman, M. & Hallbeck, S. Eur J Appl Physiol (2005) 94: 158. doi:10.1007/s00421-004-1312-1

Abstract

Work-related musculoskeletal disorders (WMSDs) in the neck/shoulder region and the upper extremities are a common problem among computer workers. Occurrences of motor unit (MU) double discharges with very short inter-firing intervals (doublets) have been hypothesised as a potential additional risk for overuse of already exhausted fibres during long-term stereotyped activity. Doublets are reported to be present during double-click mouse work tasks. A few comparative studies have been carried out on overall muscle activities for short-term tasks with single types of actions, but none on occurrences of doublets during double versus single clicks. The main purpose of this study was to compare muscle activity levels of single and double mouse clicks during a long-term combined mouse/keyboard work task. Four muscles were studied: left and right upper trapezius, right extensor digitorum communis (EDC) and right flexor carpi ulnaris. Additionally, MU activity was analysed through intramuscular electromyography in the EDC muscle for a selection of subjects. The results indicate that double clicking produces neither higher median or 90th percentile levels in the trapezius and EDC muscles, nor a higher disposition for MU doublets, than does single clicking. Especially for the 90th percentile levels, the indications are rather the opposite (in the EDC significantly higher during single clicks in 8 of 11 subjects, P<0.05). Although it cannot be concluded from the present study that double clicks are harmless, there were no signs that double clicks during computer work generally constitute a larger risk factor for WMSDs than do single clicks.

Keywords

Computer mouse Muscle activity Motor units Doublets

Copyright information

© Springer-Verlag 2005