The correlation between ART and OCRA methods used for posture assessment of repetitive tasks.

BACKGROUND AND OBJECTIVE: Repetitive tasks are among the causes of musculoskeletal disorders. Assessment of repetitivetasks is performed through various methods with different scores and significance given to risk factors considered in these methods. Knowing the strengths and weaknesses of each method can contribute to modifying the methods and improving the correlation between them. This study aimed to investigate the correlation between ART and OCRA methods in a career with repetitive movements. METHODS: After hierarchical task analysis in a vegetable grower job with repetitive movements, the subtasks were assessed by an assessor who mastered both ART and OCRA methods. The final score of each method was checked using the Pearson correlation coefficient in SPSS 18, after testing the normality of data. RESULTS: Moderate risk levels were reported for 16 out of the 14 sub-tasks analyzed using both methods. In the ART method, 3 sub-tasks and in the OCRA method, 2 sub-tasks had high-risk levels. The Pearson correlation coefficient was 0.842 indicating a moderate correlation between the two posture assessment methods. CONCLUSION: The findings of the study showed an acceptable correlation and compatibility between the two methods considering the risk levels.

Technical Report on the Modification of 3-Dimensional Non-contact Human Body Laser Scanner for the Measurement of Anthropometric Dimensions: Verification of its Accuracy and Precision.

Introduction: Three-dimensional (3D) scanners are widely used in medicine. One of the applications of 3D scanners is the acquisition of anthropometric dimensions for ergonomics and the creation of an anthropometry data bank. The aim of this study was to evaluate the precision and accuracy of a modified 3D scanner fabricated in this study. Methods: In this work, a 3D scan of the human body was obtained using DAVID Laser Scanner software and its calibration background, a linear low-power laser, and one advanced webcam. After the 3D scans were imported to the Geomagic software, 10 anthropometric dimensions of 10 subjects were obtained. The measurements of the 3D scanner were compared to the measurements of the same dimensions by a direct anthropometric method. The precision and accuracy of the measurements of the 3D scanner were then evaluated. The obtained data were analyzed using an independent sample t test with the SPSS software. Results: The minimum and maximum measurement differences from three consecutive scans by the 3D scanner were 0.03 mm and 18 mm, respectively. The differences between the measurements by the direct anthropometry method and the 3D scanner were not statistically significant. Therefore, the accuracy of the 3D scanner is acceptable. Conclusion: Future studies will need to focus on the improvement of the scanning speed and the quality of the scanned image.