Fig. 4.

COP location on the foot at foot strike (COP_locFS) versus patellofemoral joint compression force (PFJCF), with the blue circles for backward running (BR) and the red crosses for forward running (FR). There was a significant correlation between PFJCF and COP_locFS (R²=0.26 and p=0.008). Note the circled outlying trials with COP_locFS close to the forefoot and a relatively low PFJCF. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)