USE OF VISUAL-PERCEPTION IN ESTIMATING STATIC POSTURAL STRESSES - MAGNITUDES AND SOURCES OF ERRORS

Very little is known about the magnitudes and sources of errors associ ated with the visual estimation of postural classification displayed o n TV screens. This study was conducted to address this issue. Sixty-th ree subjects participated in the experiments. The findings indicate th at: (1) subjects found it difficult to evaluate upper extremity postur es (particularly the elbow and the wrist), while the postures around t he lower back were the easiest to evaluate; (2) the lower extremity po sitions affected the ability of the subjects to accurately classify po stures around the wrist, elbow, shoulder, neck, and lower back, with t he estimates being > 70% for sitting and > 60% for standing (except fo r the elbow); and (3) in general, flexion and extension are easier to evaluate than neutral and non-neutral postures.