Standing on a Double-Seesaw Device is an Easy Way to Modify the Coordination Between the Two Feet for Controlling Upright Stance: Assessment Through Weight-Bearing Asymmetry

Abstract

Healthy young subjects were instructed to modify their weight-bearing asymmetry when standing on a double-seesaw device. The results indicated decreased and unchanged amplitudes in the center-of-pressure movements under the unloaded and loaded legs, respectively. In addition, a concomitant increased contribution of the more loaded leg and a decreased contribution of the pressure distribution mechanism along the mediolateral axis were observed in the production of the resultant center of pressure, its amplitude remaining constant. Thus, contrary to what was previously reported for stance control on solid ground, one of the main characteristics of a double-seesaw device, by preventing increased amplitudes on the loaded side during weight-bearing asymmetry, would be to facilitate a greater independency of the feet in the stance control process.