Influence of vertical and horizontal whole-body vibration on selected muscles tension of employees age 50+ in relation to professional exposure to vibration (pilot study)

Patrycja Łach,Piotr Kowalski

doi:10.21595/jve.2020.20854

Abstract

The pilot study on changes of selected muscles tension caused by vertical and horizontal whole-body vibration focused on employees belonging to two professional (occupational) groups. One of these groups consisted of men aged 50 years professionally exposed to vibration and the second were men not exposed to vibration at the workplace. Tests have been conducted in two series on special designed laboratory test bench for simulation of exposure to whole-body vibration. During the I series of tests, vertical vibration had acted on subjects and during II series horizontal lateral vibration had acted. The EMG signals were registered from muscles of the shoulder girdle and lower back, both sites of the body. Muscles tension values obtained during I and II series indicates that there are no statistical significant differences between reaction of subjects on vertical and horizontal vibration. However slightly lower EMG RMS values during II series were noticed. Exposure to whole-body vibration may cause changes in muscle tension both in employees (aged 50 years and older) occupationally exposed to vibration and not exposed to vibration. The observed changes vary in both groups of subjects. In occupationally exposed to vibration subjects the impact of exposure to vibration on muscle tension is less than in reference group.

Highlights

Occupational exposure to whole-body vibration affects 4-8 % of workers in industrialised European countries [1] and more than four million workers in the USA
– the values obtained in I series for the reference group
– the values obtained in II series of tests for the reference group

Summary

Introduction

Occupational exposure to whole-body vibration affects 4-8 % of workers in industrialised European countries [1] and more than four million workers in the USA. The highest percentage of workers being regularly exposed to vibration is reported in such sectors as: construction, forestry and fishing, transport and storage and industry. Numerous studies show that [5,6,7] along with biomechanical load [8] and psychosocial factors [9] are external factors contributing significantly to the development of musculoskeletal disorders. On the basis of studies of people exposed to vibration (1-100 Hz), it was found that the lack of a feeling of fatigue (LFF low-frequency fatigue) in terms of exposure to low-frequency vibrations can cause excessive load and increase the risk of progression musculoskeletal disorders [12,13,14].

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Discussion

Conclusion