The role of ergonomic design and application of NIOSH method in improving the safety of load lifting tasks

Load lifting is the most stressful activity of the Manual Material Handling and can trigger of work-related musculoskeletal disorders of workers. Purposes of this study are determining the prevalence of musculoskeletal disorders، assessment lifting tasks by NIOSH lifting equation method، ergonomic design and assessment of its effectiveness. This analytical and interventional study was performed on 30 workers in a Porcelain Health Manufacturing industry in Hamadan. Assessment of lifting tasks by NIOSH lifting equation and determining the prevalence of musculoskeletal disorders by Nordic questionnaire was conducted. Then، construction steps and determination of the effectiveness of ergonomic design was conducted. The results showed that the most frequent musculoskeletal disorders related to back. Results of the lifting index (LI) showed that the risk of lifting load in before intervention is high (greater than 3). This value after the conducting of ergonomic intervention (load-carrying cart) decreased to moderate level (between 1 to 3). The relationship of risk average amount before and after interventions were significant (p<0. 001). Load-carrying cart designed with shelves capable of moving vertically up and down has considerable role in safe making of lifting tasks and probability of reduce the prevalence of musculoskeletal disorders and lumbar injuries will bring in the near future.