Evaluation of Shoulder Muscular Fatigue Induced During VDT Tasks

This study was designed to evaluate localized muscular fatigue induced during visual display terminal (VDT) tasks. In the experimental paradigm used, electromyography (EMG) signals were not recorded during the VDT task but during isometric contractions in which the load imposed on the shoulder muscle was kept constant. The change in mean power frequency (MPF) and the root mean square values of EMG signals with time were explored. The correspondence between these measures and the psychological rating of localized muscular fatigue also were examined. The effectiveness of the experimental paradigm and of the measures used for evaluation of localized muscular fatigue are discussed. MPF measured during isometric contraction was found to be a sensitive measure of localized muscular fatigue.