[Occupational stress of assembly line female workers in confectionery work].

Concomitant with frequent occurrence of disorders of the neck, arm, hand and low back among assembly-line female workers in confectionery work, there is an increased number of patients with occupational cervicobrachial disorders and/or low back pain. In suspicion of the close correlation between the working conditions and development of these local disorders, a field study was undertaken. The following are the results obtained. More than 90% of these assembly-line female workers consisted of inexperienced part-time employees, mostly of middle to old age. They were engaged in decorating conveyor-carried cakes with cream and chocolate. The work necessitated repetitive movements of the upper limbs and concentration of visuosensory and nervous attention in a half-sitting slouching posture. This was considered to exert excess load on the local muscles and nervous and sensory systems. The causes that intensified the local symptoms as pointed out by the workers consisted of (1) repetitive use of the arms and hands, (2) static posture during the work and (3) sustained standing position. Complaints of low back pain were conspicuous from the unsuitable height of a conveyor-belt. Thirty five percent of the female workers needed medical treatment for cervicobrachial and/or low back pain. The forced adaptation to the belt height, sustained unnatural working posture and the imposition of forced movements seemed to be the main factors in the onset of cervicobrachial and/or low back pain in interrelation with working hours. On the basis of these results, the work load on a machine-paced assembly-line was analyzed and the necessity of improvement of working conditions was discussed.