Risk Factors and Improvement Measures for Musculoskeletal Disorders among Workers Handling Heavy Loads

This study analyzed the causes of the musculoskeletal burden and the direction of improvement of workers engaged in the automobile wheel manufacturing process. The subjective symptom investigation and ergonomic analysis of 274 workers with more than one year of service at wheel manufacturing sites in A city in Korea were conducted together with RULA (Rapid Upper Limb Assessment), REBA (Rapid Entire Body Assessment), OWAS (Ovako Working Posture Analysis System), and NIOSH Lifting Equation (NLE). As a result of the investigation, the overall burden due to heavy handling and repetitive movements was remarkable. In the ergonomic analysis, the RULA and REBA scores in the casting, processing, and loading processes were evaluated as 7-10 points, confirming that immediate improvement was needed. The NLE result also showed a risk of engineering improvement, such as the lifting index reaching 2.3. In comparison with other industries, wheel manufacturing workers showed remarkable systemic and cumulative burdens due to the peculiarity of standardized repeated handling of heavy objects. Accordingly, policy and engineering measures such as redesigning work facilities and processes, introducing automation and auxiliary devices, adjusting manpower allocation, and strengthening special health diagnosis are required beyond simple management improvement. Future research on the musculoskeletal system shows that the subjective burden level and scores through ergonomic evaluation tools should be reflected in combination, regardless of whether it is simply a burden task. In addition, this study provides basic data for establishing policies to prevent musculoskeletal diseases not only in the wheel manufacturing industry but also in industries where repeated handling of heavy objects is inevitable.