Subject-based rating of hand-wrist stressors.

Subject-based rating (SBR) methods (eg, Borg Scales) have been applied to lifting and exertion estimation. SBR methods were applied to hand-wrist motions in this controlled experimental study of rapid motion. Seven normal volunteers performed lift actions with several combinations of wrist position (flexion-extension), repetition frequency, force, and grip type (precision vs power) using an experimental apparatus. Wrist position and frequency were confirmed using an electrogoniometer. Subjects rated the tasks along 5 scales. Analysis showed that grip type had the predominant effect on the subjective ratings, but the other factors were also rated. However, cycle times between 3 and 8 seconds were not well differentiated. The study indicates that SBR does validly reflect actual stressors and suggests that SBR may be useful for "screening" jobs for more intensive study.