Development of the quantitative model for application of workers' expertise in evaluating manual lifting tasks

The objective of this paper is to investigate how worker expertise can be used to evaluate industrial lifting activities, with the ultimate goal of preventing lower back injuries in the workplace. Twenty-two professionals and twenty-two skilled laborers participated in the study. The results indicate that it is possible to use personal knowledge and experience in evaluating injury risks of physical tasks such as lifting. There was no difference between professionals and skilled laborers in terms of the cognitive patterns relating input to output variables. In the open lifting model, the weight of load was the most important variable in evaluating lifting activities, in agreement with findings in the literature about the association of task variables with back injuries at the time of the accident. In the closed loop model, perceived risk emerges as a primary variable in determining the effort level exerted during lifting activities followed by the weight of load.