the effect of increased manufacturing rate on risk of low back pain

Increasing production rate in manual handling jobs can expose workers to the risk of low back pain ) lbp(; thus, it is necessary to investigate the relationship between manufacturing rate and the risk of the lbp in order to prevent workers from being injured. the current study was aimed to survey the effect of increased manufacturing on the risk of the lbp. this cross-sectional descriptive study was conducted in a melting and casting factory in qazvin in 2015. the target population included seven workers with different occupational tasks. working steps included data collection (filming, site visit and interview), classification of the occupation to tasks and subtasks, and finally analysis of manual material handling tasks by the revised niosh equation. the composite lifting index (cli), frequency-independent lifting index (fili), and single-task lifting index (stli) of each occupation were analyzed and calculated using the manual material handling instructions of the american institute for occupational safety and health. the stli was assessed in all the unauthorized jobs. in most of the analyzed tasks, the fili had no significant difference with the stli. the horizontal distance factor (hm=0.5) had much more effect on the risk of the lbp, compared with the frequency factor (fm=0.86). the tasks of alloy ingot loading in melting and ingot job and lifting from the highest pallet row to the visiting table in visiting test job acquired the highest (stli=3.80) and lowest (stli=0.96) stli values, respectively. the maximum cli was calculated for decorating and grinding job (cli=4.96). increased manufacturing was associated with the concept of increased lifting frequency. accordingly, the investigations showed that lifting frequency had no role in developing the lbp, and the most critical effective parameter was the horizontal factor. by correcting the horizontal factor through education and elimination of the nonergonomic handling habits, the risk of the lbp could be considerably reduced.