Survey of Correlation between Two Evaluation Method of Work Related Musculoskeletal Disorders Risk Factors REBA& RULA

Abstract

Background and aims   Musculoskeletal disorder is one of the biggest occupational health problems in workplaces of industries. According to the national statistics, the proportion of musculoskeletal diseases of all occupation diseases in the United States is 44% (Bureau of Labor Statistics, 1996). On the basis of report of National Institute Occupational Safety and Health of USA(NIOSH), WMSDs is in the second place between the work-related diseases. Poor working  postures constitute one of the main risk factors for musculoskeletal disorders. Recognition,  evaluation and control action for prevention of occur disorders is important to protect and  promotion of workers health. For evaluation of WMSDs risk factor, various methods have been  presented. Two practical methods for analyzing and controlling poor working postures in  workplaces are REBA and RULA.   Methods   This research is a cross-sectional study that was conducted in order to survey of  correlation between two evaluation methods of WMSDs risk factors REBA& RULAin one of the ophthalmic lens manufacture factory.At first, jobs were surveyed and all subtasks of jobs recognized and 40 jobs out of 77 were selected. Then REBA& RULAmethods were carried out  for this jobs. Also, The final scores and action levels were determined.   Results   The result revealed that: there was a significant correlation between final score of two  methods (r = 0.781) and action levels of two methods (r=0.821). Compare to action levels, two  methods in all jobs showed that There was no significant difference between action levels at jobs  (p = 0.16) also between action levels of two methods in any of workplaces separately.  Result of REBA& RULAmethods revealed that risk level of lower arm, upper arm and wrist was  higher than trunk, neck, and legs because of awkward posture of the mentioned parts. Result of  RULAand REBAtechnique indicated that, action levels of all jobs were not acceptable.   Conclusion   On the basis of mentioned result above, this study indicated that, there was no  significant correlation between two methods and methods have a strong correlation in identifying  critical work site and determining critical limb. Therefore, both methods are recommended for   evaluation of work-related musculoskeletal disorders risk factors in industrie