The Generalizability of Psychophysical Ratings in Predicting the Perception of Lifting Difficulty

Psychophysical rating scales have been used as a parameter in lifting guidelines for workers in industrial settings, used to identify musculoskeletal disorders in the workforce, and used as a surveillance tool to identify workforce discomfort. These scales can be an inexpensive and easy-to-use tool for evaluating a large variety of exertions, especially those which are difficult to evaluate using current biomechanical and physiological models because of complex dynamic or asymmetric movements. In order for these scales to be used quantitatively, however, it is essential that they consistently represent the same level of perception across different subjects and tasks. Twenty subjects rated a variety of elbow flexion exertions on the Borg CR-10 scale under two task formats. The intra-subject, inter-subject, and inter-task variations were measured. Results indicate that the Borg CR-10 scale provides a consistent measure of psychophysical perceptions across a variety of task parameters.