A comparison of RULA, REBA and Strain Index to four psychophysical scales in the assessment of non-fixed work.

Objectives: The objective of this study was to evaluate the efficacy of three ergonomic assessment tools (EATs) (RULA, REBA and Strain Index (SI)) in the assessment of non-fixed work through comparison to four occupationally relevant Borg 10 psychophysical scales: Lifting Effort, Grasping Effort, Wrist Discomfort, and Low Back Discomfort.
Participants: Fourteen male rodworkers participated in this study. The participants had at least six months experience and had no musculoskeletal injuries in the six months preceding their participation.
Methods: Psychophysical scale and video data were collected while participants performed non-fixed work on construction sites. Psychophysical and EAT outcome measure scores were calculated for a shortlist of tasks.
Results: It was found that the perceived Grasping Effort and Wrist Discomfort scales differentiated between the WMSD risks associated with rodworking tasks and SI was found to be more effective than RULA and REBA in the assessment of non-fixed work WMSD risks.
Conclusions: Based on the findings of this study, it is suggested that SI be further evaluated for its ability to assess WMSD risks associated with non-fixed work tasks. SI presents results that have practical application to non-fixed occupations and differentiate between tasks based on the WMSD risks associated with the tasks.