Comparing dynamic and stationary standing postures in an assembly task

Prolonged standing during monotonous tasks such as assembly line jobs may lead to musculoskeletal disorders including increased fatigue, pain and stiffness in active muscles. This study evaluated the efficacy of a dynamic standing posture over the stationary standing posture in reducing physical stress using sEMG and psychophysical analysis. From the sEMG study, it was found that the fatigue rates in leg and lower back muscles were significantly higher (p < 0.05) in the stationary standing posture as compared to the dynamic standing posture. This finding was corroborated by the results of psychophysical test. Ergonomic design of the dynamic posture that has been proposed in this study can be easily absorbed into most shop-floors to decrease the incidence of musculoskeletal disorders. Relevance to Industry: The proposed dynamic standing can decrease fatigue and risk of acquiring lower extremity disorders than a stationary standing during shop-floor and assembly line duties. Dynamic standing is simple to implement and can be incorporated in existing assembly line. This can improve occupational safety by reducing work-related musculoskeletal disorders. (C) 2008 Elsevier B.V. All rights reserved.