Postural Sway And Muscle Activity Dynamics Of Standing On Sloped Surfaces

Abstract

The purpose of this study was to investigate how standing at different degrees of plantarflexion and dorsiflexion influence (1) postural sway and muscle activity and (2) the relationship between muscle activity and postural sway. An additional purpose was to investigate the effects of vision on postural sway and muscle activity while standing on sloped surfaces. Participants (N=12) stood on an angled platform, which provided a continuous inclined or declined perturbation to their stance at varying difficulty. The angled platform was situated atop a force plate, which allowed for center of pressure (COP) evaluation. Electrodes were placed on the dominant leg for electromyography (EMG) measurements of plantarflexor and dorsiflexor muscles. Results showed the amount of postural sway increased as a result of increased difficulty and the removal of vision. Additionally, muscle activity was influenced by postural difficulty, but not as hypothesized. Finally, postural difficulty altered the relationship between COP and EMG.