Tag: Chou Li-Shan

Presenter: Eric Pisciotta, Human Physiology

The trajectory of the center of pressure (COP) has been shown to be a valid and reliable tool for assessing foot function. The purposes of this study were to quantify changes in the position of COP relative to the foot during stance, examine changes in the AP and ML excursions of the COP, and to quantify changes in the variability of the COP trajectory between shod and barefoot (BF) running conditions. Utilizing a force plate and an 8-camera motion capture system, the average AP and ML position of the COP trajectory was calculated relative to the heel marker at each instant, for each foot, in a group of ten habitually shod recreational runners. (Mean age 32.4 ± 4) The variability was also calculated and plotted in increments of 10% stance. The COP was located significantly more medially at all time points in the BF condition compared to shod running. The trajectory of the COP during the BF condition was marked by a more medial location under the foot throughout stance, a more anterior position at initial contact, and reduced AP excursion. No significant differences were found in the variability of the COP trajectory or ML excursions. This suggests, apart from the initial contact position, the dynamics of foot roll over are similar between shod and
BF conditions. The few COP differences that were observed in this study are similar to COP characteristics that have previously been shown to be related to injury. Therefore future studies should examine how or if these changes may be related to injury risk during BF running.