Risto Toivonen, Esa-Pekka Takala Finnish Institute of Occupational Health, Helsinki
There is a general agreement of the relationship between visual display unit (VDU) work and a high prevalence of musculoskeletal symptoms. Individual, psychosocial, work organisational and biomechanical factors have all been associated with problems in the upper body and extremities ( Punnett and Bergqvist 1997). However, exact epidemiological data about the relationship between physical workload and musculoskeletal symptoms is missing.
The aim of this paper is to introduce a method to be used in the assessment of dose-response relationship between VDU work and discomfort.
Feeling of comfort/discomfort in a body part can be used as an indication of localised muscle fatigue during work. Uncomfortable feeling may reflect metabolic changes in a muscle. These changes will disappear if muscle is allowed to rest. However, if not enough rest is allowed, more advanced changes in a muscle may develop and manifest as musculoskeletal symptoms. This hypothetic situation is presented in figure 1. Symptoms are assumed to cumulate during the workweek. During the weekend there is a long enough pause for muscles to take a sufficient rest.
We can further set a hypothesis that the amount of daily workload has an effect on the cumulation of discomfort.
To assess dose-response relationship in VDU work, we should, according to our hypothesis, see a relationship between computer usage and feeling of discomfort