The main purpose of this study was to investigate relationship between cumulative trauma disorders(CTDs) and the types of workstation and chair in workers with repetitive motion tasks.

The study subjects were 77 repetitive motion tasks workers at small manufacturing industries in Seoul and Gyung-gi district area. A questionnaire was used to obtain about health practice for prevention and prevalence of CTDs by worker. The type of Workstations and chairs in workers were measured and analyzed with prevalence of CTDs by logistic regression.

Eighty-six percent of workers recognized that work posture was related to workstation and chair. Most employers and employees didn't follow the work practice guidelines for workers with repetitive motion tasks. The prevalence of CTDs was 64% by questionnaire. The prevalence of pain in shoulder, neck, back, and arm were 38%, 15%, 6%, and 5%, respectively, and the pain started after working an average duration of 16.5 months. The CTDs symptoms were significantly related to thickness of workstation, height of workstation, length of knee depth under workstation, height of back rest, height of seat pan, depth of sitting surface, width of sitting surface, and length from workstation surface edge to shoulder. By multiple regression analysis of each risk factor, prevalence of CTDs was highly correlated with height of back rest, height of seat pan, and depth of sitting surface.

This study suggests that workstations should be made adjustable for height and chairs should be equipped with seat pan height control, enough sitting surface for depth and width, back rest height and angle control. The workers should use the right working postures, exercise for health, occupational health education, and rest breaks and the manager of company should be educated for the preventing of CTDs.