Effects of load carriage and surface inclination on linear and non-linear postural variability

Abstract

Understanding of inclined-work-related risk of falls and developing novel practical engineering controls for reducing this risk of falls among hilly working population remains in high demand. Standing on sloped surfaces provides a unique environment for examining the biomechanics and neural control of standing. The present investigation examined the variability of postural signals when standing on inclined surfaces and with load carriages by linear and nonlinear analysis. The purpose of this study was to determine if the sloped surface deteriorated in postural stability among healthy individuals with two distinctive kinds of load carriage methods head versus posterior load carriage. We also examined the effects of distinct magnitudes of load on these conditions. Postural control was assessed objectively using forceplates and subjectively through perceived stability ratings. The results indicate significant differences in mediolateral COP ranges, COP velocities and COP area with interaction in surface inclinations and methods of load carriage. We found that head load carriage when standing on uphill afflicted and engendered increased balance deterioration in healthy young subjects. We also found the significantly lower complexity of postural signals for head load carriage as measured by entropy. Apropos to this mean subjective perceived rating was also least in this load-bearing condition. Understanding these underlying mechanisms of postural control with load carriage strategies in humans could productively help in developing efficacious preventive strategies to reduce the incidence of falls from inclined slopes.