Postural stability during task performance on elevated and/or inclined surfaces

Abstract

The purpose of this study was to subjectively and objectively evaluate the postural stability of forty industrial workers while performing simulated industrial tasks on inclined and elevated surfaces under various combinations of environmental lighting and noise distraction conditions. The results suggest the following ordering for the effects of risk factors on objective measure of postural balance: (1) environmental lighting, (2) elevation of standing surface, (3) gender, (4) inclination of standing surface, (5) age. The task performed would be ranked highest had the data been analyzed across the three tasks. The postural sway length significantly increased with increasing elevations and inclination angles for the stationary and bending tasks implying body's perceived risk of fall deployed increase in postural muscle contraction. This compensatory mechanism indicated by increased sway length actually did reduce postural sway amplitudes with increasing elevation but for increasing inclination the postural sway amplitudes increased. While the objective measure of postural sway increased with the increasing combination of elevation and inclination, the subjective measure of stability did not show a significant two way interaction, implying that the participants were not able to perceive the combined risk to postural imbalance, causing potential inability to deploy appropriate postural muscle corrective actions.