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Effects of arm position and platform perturbation velocity on postural sway

1 May 1991


The purpose of this study was to investigate the center of balance and postural sway responses of normal individuals to different arm positions and velocities of platform perturbation. Ten males and eighteen females were studied. Each subject stood on two footplates placed on a moveable balance platform and was perturbed with horizontal translations of four velocities ranging from 0 to .191 cm/sec. Each subject was perturbed in a stance posture of arms crossed across the chest and arms at sides. Center of balance and postural sway measurements were obtained. The results demonstrated that subjects stood with a center of balance significantly (p < 0.05) closer to their toes with their arms crossed in front of the chest than with their arms down at their sides. No significant difference in postural way in static stance with the two arm positions was found. The results also revealed that subjects displayed significantly (p < 0.05) greater amounts of postural sway when perturbed at the two fastest speeds (.127 and .191 cm/sec) than the slowest speed (.065 cm/sec). However, no statistically significant interaction effect was found between the arm position and velocity of perturbation.


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