Perception of efforts in working postures.
The aim of this study is to obtain an understanding of the subjective discomfort of working postures and the degree of physical effort these postures give rise to. 31 students have rated their perceived exertion on Borg's scale (1982) based on a collection of photographs of different work postures of varying complexity, including a kinaesthetic description. Each one of the 78 postures was held for 45 seconds, with rated perceived exertion (RPE) given after 15, 30 and 45 seconds. The whole test series was repeated twice. The results show that it is possible to evaluate different body postures by RPE achieving a total reliability alpha-value over 0.96. Despite the fact that the rating pattern between the different postures was the same for all subjects, it is shown that each person assessed according to a certain individually-influenced pattern. A certain person can for example, deviate consistently towards higher values on Borg's scale, a so-called "high rater". Finally, the different postures were grouped according to how the ratings changed in time (regression slope between the RPE's after 15, 30 and 45 seconds). The third-cluster, which showed a high basic rating-level and the greatest regression slope, included only extreme outer limits of movement. This indicates that the outer limit postures have a tendency to static load and need to be studied by more additional methods when remaining unchanged even for short periods.