Effects of work and rest on upper extremity signs and symptoms of workers performing repetitive tasks.

The temporal relationship between work and signs and symptoms of upper extremity musculoskeletal disorders among workers at risk is relatively unexplored. The study focused on changes in upper extremity circumference, volume, sensory threshold, and reported symptoms after work and rest. All workers (N=50) performed a repetitive poultry processing task and had exhibited upper extremity signs and symptoms in baseline testing prior to this study. These workers manifested significantly increased upper extremity circumference following a period of rest, with circumferences decreasing during work. Upper extremity volume and reported swelling also decreased during work. Reports of tenderness were significantly greater after work than after rest, while reports of pain were greatest after a short rest interval. Results show that the signs and symptoms observed in these workers were manifestations of occupational cumulative trauma and that further study of the relationship between work and signs and symptoms is needed.