ergonomic risk assessment of lifting activities; a case study in a rubber industry

manual material handling is identified as one of the musculoskeletal disorders risk factors. the aims of this study were to evaluate lifting activities by niosh equation and mac method and the correlation of these two methods. this cross-sectional study was conducted in a rubber industry. studied subjects were 136 male workers selected from various sections by proportional-to size sampling method. data were collected using demographic and nordic musculoskeletal disorders questionnaire (nmq). lifting activities were evaluated by niosh equation and mac method. statistical analyses were performed using spss, version 16 and some tests such as independent sample t test, chi-square (χ2) and bland-atman test. the level of significance was set at <5%. the means of age and job tenure in subjects were 33.31±6.48 and 9.77±6.17 years, respectively. prevalence of msds was 77.2%. the results revealed significant association between msds risk level evaluated by niosh and mac methods and musculoskeletal disorders occurrence. the correlation of the two lifting activity evaluation methods was significant (p<0.05). based on the findings of the present study, the evaluated risk level by the two evaluation methods and prevalence of msdshad significant relationship. the correlation result indicated that mac method can be used interchangeably with niosh equation for ergonomic evaluation of lifting activities.