Application of center-of-pressure data to indicate rearfoot inversion-eversion in shod running

Although pressure plates are used to help in the selection of appropriate footwear for runners, evidence relating aspects of pressure data to movement is lacking. A study was conducted to investigate whether center-of-pressure (COP) data obtained for shod running could be used to indicate the amount of rearfoot eversion. It was hypothesized that subjects exhibiting high rearfoot eversion during the initial ground contact phase of running would also show a large lateral-to-medial deviation in the COP. Pressure plate and rearfoot movement data were collected for 33 subjects. The COP was characterized using the lateral-to-medial deviation of the COP during the eversion phase of ground contact. Correlation coefficients were determined for COP deviation versus rearfoot range of motion and versus peak rearfoot eversion (P < .05). In addition, subjects were grouped as high, moderate, or low pronators, and analysis of variance was used to test whether there were significant differences in COP deviation for these three groups (P < .05). The COP deviation was found to have a low correlation with rearfoot range of motion (R = 0.46; P < .05) and with peak rearfoot eversion (R = .54; P < .05). High pronators had significantly higher COP deviation than the medium- and low-pronation groups (P < .05). These findings support the use of COP deviation to detect high pronation. However, caution is advised in using the COP to indicate absolute rearfoot eversion.