Mohsen Sadeghi Yarandi - Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Ahmad Soltanzadeh - Department of Occupational Health Engineering, School of Health, Qom University of Medical Sciences, Qom, Iran
Alireza Koohpaei - Department of Occupational Health Engineering, School of Health, Qom University of Medical Sciences, Qom, Iran
Ali Asghar Sajedian - Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Vahid Ahmadi - Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Sogand Sakari - Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Saeid Yazdanirad - Department of Occupational Health Engineering, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.

Background and Aims of the study: Work-related musculoskeletal disorders (WRMSDs) are among the most common types of occupational diseases and damages, especially in repair and maintenance occupations. There are various methods for the prediction of the risk factors affecting the prevalence of WRMSDs. This study aimed to determine the effectiveness of three ergonomic risk assessment tools, namely the Novel Ergonomic Postural Assessment (NERPA), Rapid Upper Limb Assessment (RULA), and Rapid Entire Body Assessment (REBA), for screening the musculoskeletal disorders in the employees of repair and maintenance occupation in a power plant equipment industry in Alborz province, Iran, in 2017. Materials and Methods: This cross-sectional study was carried out on all employees in the repair and maintenance department of a power plant equipment industry, including 295 subjects in six occupational groups. The General Nordic Questionnaire was used to determine the levels of musculoskeletal disorders. The REBA, RULA, and NERPA methods were employed in order to predict the risk of developing musculoskeletal disorders. Finally, the data related to the real values of musculoskeletal disorders and risk values predicted by the three mentioned methods were analyzed through Spearman’s rank correlation coefficient and kappa agreement coefficient at the significance level of 0.05 using SPSS software (version 25). Results: Mean age of the participants was reported as 37.52±3.61 years. Correlation values between the levels of musculoskeletal disorders and risk levels predicted in the RULA, NERPA, and REBA were observed to be 0.764, 0.723, and 0.689, respectively (P<0.05). Correlation coefficient values of the risk levels predicted in the RULA method with NERPA and REBA were 0.767 and 0.620, respectively (P<0.05). Conclusion: Based on comparing the correlation level of prevalence rates of musculoskeletal disorders with predicted risk levels in the three studied methods, the results indicated that the best method for predicting the risk of musculoskeletal disorders in different examined tasks was the RULA method. However, none of the methods had adequate comprehensiveness for the assessment of all four risk levels.  

Musculoskeletal Disorders, NERPA, RULA, REBA, Repair and Maintenance.