The Influence of Aging on the Center of Pressure Trajectory: a Comparison of Crossing an Obstacle and Stepping onto a Curb from a Position of Quiet Stance

Abstract

[Purpose] The purpose of this study was to investigate how young and older adults modulate the center of pressure (COP) trajectory and stance time during obstacle negotiation. [Subjects] Fifteen healthy young adults and fifteen healthy older adults participated in the study. [Methods] The subjects stepped over an obstacle (18 cm in height, 10 cm in breadth and 140 cm in width) and a curb (18 cm in height, 140 cm in breadth and 140 cm in width) at a self-paced speed from a position of quiet stance. Performance was assessed by recording changes in the displacement of COP in the anteroposterior (A-P) and mediolateral (M-L) directions, and by measuring the average velocity of the COP and stance time using a force platform. [Results] The A-P and M-L displacement of COP and the average velocity of COP of the older adults were significantly less than those of the young adults (p<0.01). The stance time of the the older adults was significantly greater than that of the young adults (p<0.01). However, the COP variables between the stepping tasks were not significantly different. [Conclusion] The COP shift and velocity and stance time during obstacle negotiation might be appropriate parameters for evaluating the dynamic balance and motor control strategies of older adults.