Ergonomic Risk Assessment of Distal Upper Extremities by Job Strain Index in Carpet Weavers

Abstract

Background: Distal upper extremities musculoskeletal disorders (DUEMSDs) is considered as the main cause of working lost time, increased labor costs, and human injuries. This study was conducted to assess the risk factors of DUEMSDs in carpet weavers. Methods: This descriptive cross-sectional study was conducted on 143 carpet weavers located in Qom city. For quantifying the prevalence of signs or symptoms of DUEMSDs, the customized nordic musculoskeletal questionnaire (NMQ) was used. Next, carpet weaving jobs were analyzed by hierarchical task analysis (HTA). All risk factors that caused DUEMSDs were determined and risk assessment of DUEMSDs was done by the Job Strain Index (JSI). Results: Nordic musculoskeletal questionnaire results (NMQ) showed that the most prevalent of disorders was related to the upper back (62.2%), lower back (60.1%), wrist (55.9%), and shoulders (37.2%), respectively, during the last year. Also, JSI results showed that sub-tasks of knot tying and cutting, milling, shoulder milling headband, and the sub-tasks paid in the area were placed in the hazardous category. Among the parameters of the strain index, duration of exertion, effort in minutes, and hand/wrist posture had the most important effect in the creation of the risky level knot (W4), cutting the knots (W5), and combing (T6) sub-tasks. Also, duration of exertion and hand/wrist posture had the most important effect in the creation of the risky level in head band milling (R1) and combing (R7) sub-tasks. Conclusions: Knot and cutting sub-tasks in the task of weaving, as part of carpet weaving jobs, were the most hazardous sub-tasks. Implementation of ergonomic interventions focused on reducing the duration of exertion, efforts in minute, and correction of hand/wrist postures may improve workstations and reduce distal upper extremities musculoskeletal disorders risk factors in carpet weaving workers.