Comparison of ergonomic risk assessment output in a repetitive sawmill occupation: trim-saw operator

Multiple ergonomic risk assessment methods of unique structure are currently being used to direct industrial prevention initiatives focused on musculoskeletal injuries. In this study, the physical exposures required to perform an at-risk sawmill occupation were collected from 29 subjects via quantified means (surface electromyography and electrogoniometery) and used to calculate several ergonomic risk assessment methods. The aims of this study are to: 1) compare the output of the RULA, REBA, ACGIH TLV, Strain Index and OCRA ergonomic risk assessment methods, 2) examine the assessments' ability to differentiate between facilities reporting meaningfully different incidence rates, and 3) examine the effect of varying the definition of end range posture and exertion required on risk assessment scores. Risk level output assigned by all methods were not sensitive to inter facility differences in risk of injury, suggesting interpretation of risk index and component scores are needed to direct intervention. Components of all methodologies were sensitive to worker technique and facility assessed. Varying variable definition resulted in significantly different component, combined component and/or risk output scores in all methods assessed. The significant effect of posture and exertion variable definition suggests definitions taken to be interchangeable by work site evaluators are not equivalent.