Comparison of Novel Ergonomic Postural Assessment and Rapid Upper Limb Assessment Methods for Evaluating the Posture of Employees in an Agricultural Equipment Manufacturing Company in 2017

The observational methods are the most common techniques for postural assessment. Afterwards, preventive interventions for musculoskeletal disorders are performed as the best strategy. Therefore, the most important point in the first phase is the selection of suitable assessment method. With this background in mind, this study was conducted to evaluate the correlation and agreement between the results of Novel Ergonomic Postural Assessment (NERPA) and Rapid Upper Limb Assessment (RULA) methods to determine the appropriate technique. In the current study, 41 postures were investigated following the exclusion of similar postures. Photos of postures were prepared and assessed according to the instructions of NERPA and RULA methods by an assessor. The score of each organ and the final risk level of both methods for right and left sides were evaluated by the Wilcoxon method. Moreover, the results were compared using the Spearman correlation coefficient and the Kappa coefficient. Our findings indicated that higher scores for risk levels 1 and 2 were obtained by  NERPA method, while the RULA score was higher for levels 3 and 4. It should be noted that the mentioned difference was significant for the right side. In terms of the scores of body organs, there was a significant difference in the wrist score. The results of analyses demonstrated that the correlation coefficient of NERPA and RULA methods for left and right sides was 0.605 and 0.697, respectively. Furthermore, the Kappa agreement coefficient was revealed as 0.206 and 0.401 for left and right sides, respectively. According to the results of the present study, NERPA method identified the low risks better than RULA technique. As a result, considering the involvement of the freedom degree of body organs in neutral zone in NERPA method and the significant difference between the two techniques, NERPA application is recommended. On the other side, although the two methods did not have a good agreement, the results showed that they were correlated. Therefore, both methods can be used in industries similar to the current investigation.