A Comparative Assessment of Ergonomic Risk Factors in University Personnel Using RULA and REBA Aiming to Study the Cause and Effect Relationship

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The aim of this research was to conduct an ergonomic assessment of working postures and the design of computer workstations of the employees in Louisiana State University. The purpose of the study was threefold- (1) to determine the major ergonomic issues in university employees while working on computer workstations, (2) to compare the two ergonomic assessment tools (RULA and REBA) to see how similarly or differently they assess the risks present in the same working condition and (3) to develop a model that correlates between working condition, work posture and computer workstation design with their effects on musculoskeletal system. This research was constituted of a comprehensive survey (5 minutes) and a quantitative risk assessment session (20 minutes) conducted over 72 participants and their workstations in the university workplace. Along with the pre-assessment questionnaire; the Cornell Musculoskeletal Discomfort Questionnaire (CMDQ) and two ergonomic assessment tools REBA (Rapid Entire Body Assessment) and RULA (Rapid Upper Limb Assessment) were used to quantify the ergonomic risk factors. To evaluate the computer work stations “OSHA Computer Workstations eTool - Evaluation Checklist” was used. The most number of participants (75.71%) reported to suffer from upper and lower back pain. Next to it was shoulder and upper arm (45.71%) and then forearm and wrist (42.85%) discomfort. Average RULA score (5) was more than that of REBA (4) making RULA an assessment tool with better consistency while evaluating activities of upper limb, as working on computer workstation. In 85.48% of cases RULA score was the same or more than that of REBA which indicates the strenuous work of office employees cause a disorder more in the upper limbs than that of the lower limbs. Proportional odds ordinal regression model was used to identify the most significant factors contributing towards the WMSD symptoms which are, (1) inappropriate positioning of computer monitor and exposure to prolonged awkward posture of the (2) trunk or torso, (3) shoulder-upper arm, (4) forearm-elbows and (5) wrist and hand. Three equations were developed for predicting the probabilities of a user having slightly, moderately or very uncomfortable pain when the postural and design factors are given.