Ergonomic models of musculoskeletal strain in computer work have focused primarily on biomechanical indices (e.g. key force, keystroke repetition, work posture); relatively little attention has been given to psychophysiological indices (e.g. hyperventilatory responses to mood disturbances). This report explores the relationship between psychophysiological and biomechanical factors with right-hand musculoskeletal strain in 47 data-entry computer workers. Self-ratings of right-hand musculoskeletal strain (i.e. discomfort, pain, stiffness, or soreness), boredom, and fatigue were taken during prolonged periods of data-entry work during each of three consecutive workdays. End-tidal Pco2, key force, and keystroke repetition were monitored on a continuous basis. An examination of changes in these measures indicates consistent increases in right-hand musculoskeletal strain within each of the three workdays. In addition, there was a corresponding pattern of psychophysiological strain, as characterized by increases in boredom and fatigue and decreases in end-tidal PCO* (i.e. hyperventilation) within each of the three workdays. However, there was no consistent pattern of increases in key force or keystroke repetition. These results suggest that the psychophysiological demands (i.e. chronic mild hyperventilation) of mood disturbances attendant to repetitive computer work are associated with right-hand musculoskeletal strain. It is proposed that ergonomic models of musculoskeletal strain in repetitive computer work should be expanded to include psychophysiological stress factors in addition to conventional biomechanical stress factors.
Biological-effects; Stress; Statistical-analysis; Musculoskeletal-system; Repetitive-work; Computer-equipment; Computers; Posture; Psychological-effects; Psychological-fatigue; Psychological-processes; Psychological-responses; Physiological-effects; Physiological-fatigue; Physiological-measurements; Physiological-response; Biomechanics