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Biomedical subjects

M Wangenheim

Publications and source records attributed to M Wangenheim.

7 recordsLinked to original sources
PubMed1987

A psychophysical study of work-related stress using observer ratings.

In two experimental series a panel of observers rated the perceived exertion of a worker performing different tasks. The first experiment involved the lifting of boxes of different weights. The second experiment comprised combined static and dynamic work of the assembly-line type during a full working day. The results show that the observers were able to discriminate between the different loads in all stress situations. Since the loads ranged from low to maximal stress, all were able to make assessments over the full range. Furthermore, the relationship between observer ratings and self-ratings approximated a logarithmic function with the observers tending to overestimate the low stresses while there was closer agreement in the rating of high stresses.

Humans↗
PubMed1986

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.

Adult↗
PubMed1984

Measurement of whole-body vibration by double-pulsed holography.

A technique for registering vibration and deformation patterns has been adapted for the measurement of whole-body vibration in humans. Double-exposure holographic interferometry produces three dimensional pictures of the body, allowing exact measurement of the subject's movement between the two pulses. In this study an interval of 600 microseconds between the two pulses was used, producing measurements with a resolution of less than 0.3 X 10(-6)m. The subject standing in a fixed posture, was exposed to the laser beams first without vibration and then with vibration. The picture without vibration is needed as certain movements due to life functions of the body such as heartbeat, blood circulation etc are involved therein. This basic pattern should be considered when analysing the pictures with vibration. Different types of vibration in various postures were studied. Tests were also conducted when a reflective coating was applied to the skin. The results show that the method is applicable for measuring whole-body vibration and suggests further tests with more modern laser equipment which is now available. Such equipment can produce pulses with a high repetition rate and of much better quality than those obtained in this study. Once coordinated to the heartbeat and to the working frequency of the vibrating object, a reliable analysis of whole-body vibration can be maintained.

Holography↗