Background and purpose: Musculoskeletal disorders (MSDs) are common and important health-social problems in industrial societies that reduce productivity, increase treatment costs, and reduce the quality of life of workers. The present study was conducted with the aim of investigating the effect of workload, fatigue, sleep quality and physical condition on musculoskeletal disorders of steel industry workers.
Method: The present study was a descriptive and analytical study that was conducted on a population of 540 workers working in the steel industry of Dezful city. Based on simple random sampling, 400 people were selected as samples. The tools used in this research are people's demographic information questionnaire, Cornell Musculoskeletal Disorders Questionnaire (CMDQ), Swedish Occupational Fatigue Inventory(SOFI), Pittsburgh Sleep Quality (PSQI) and NASA-TLX workload index. Rapid Entire Body Assessment (REBA) was used. Descriptive statistics indices were used to analyze the data and Structural Equation Model (SEM) was used to examine the relationships between observed and hidden variables. The data were analyzed at a significance level of 0.05 and in SPSS software version 25..
Findings: According to the prevalence of musculoskeletal disorders, back pain with a mean and standard deviation of 52.39±25.44 ranked first and knee pain with a mean and standard deviation of 46.46±26.45 ranked second, indicating The prevalence of these disorders is high among steel industry workers. The results of the correlation analysis showed that there is a positive and significant relationship between workload, fatigue, sleep quality and body condition with musculoskeletal disorders (p<0.05). According to the RMSEA index less than 0.1, the proposed model in this study had a good fit and showed the role of workload variables, fatigue, sleep quality and body position in causing musculoskeletal disorders directly and indirectly.
Conclusion: The results of this research show that improving the workplace ergonomics, reducing workload, fatigue and improving sleep quality can reduce the likelihood of musculoskeletal disorders in worker