The primary aim of this study was to evaluate the predictive validity of the Strain Index and compare it to predictions based on the presence of generic risk factors within turkey processing. Data was gathered and a Strain Index Score was assigned to a total of 56 jobs-by-sides at a turkey A job was classified as 'problem' or 'safe' based on the presence or absence of a generic risk factor. The morbidity classification for jobs-by-sides was 'positive' if there was at least one recorded distal upper extremity disorder corresponding to that job and that side of the body and 'negative' if no such disorders were recorded. The Strain Index classified 39 jobs-by-sides as 'problem' and 17 as 'safe.' Forty-two of the jobs-by-sides were 'positive.' Among categorical variables, intensity of exertion, duration of exertion, hand/wrist posture, speed of work, and duration per day ratings were significantly greater for 'problem' jobs-by-sides compared to 'safe' jobs-by-sides. Among continuous variables, the percent duration of exertion processing facility. The hazard classification for a job was 'problem' if the Strain Index Score was five or greater and 'safe' if the Strain Index score was less than five. The generic risk factors considered in this study included repetitiveness, pinch grasp, hand - arm vibration, and cold temperature. The Strain Index Scores were significantly greater for 'problem' jobs-by-sides compared to 'safe' jobs-by-sides. The Strain Index ratings for intensity of exertion, duration of exertion, and duration per day were significantly greater for 'positive' jobs compared to 'negative' jobs. Among continuous variables, percent duration of exertion, production cycle time, and the Strain Index Score were significantly greater for 'positive' compared to 'negative' jobs-by-sides. Two generic risk factors, cold temperature and pinch grasp, were negatively associated with morbidity. As a screening tool to identify 'positive' versus 'negative' jobs-by-sides in this study, the Strain Index methodology had a sensitivity of 86%, specificity of 79%, positive predictive value 92%, and negative predictive value of 65%. The results of this study concur with the Strain Index methodology that exertional demands of a task best explain the occurrence of distal upper extremity disorders within a job.
Includes bibliographical references (leaves 50-51).
Knox, Kristine Renee (2000). Validation of the strain index: poultry processing. Master's thesis, Texas A&M University. Available electronically from http : / /hdl .handle .net /1969 .1 /ETD -TAMU -2000 -THESIS -K62.