Figure 5. Definition of the variables and phases. From the outside phase, mean (vGRFmean) and maximum forces (vGRFmax) were calculated. From the inside phase, mean (vGRFmean) and minimum (vGRFmin) forces were calculated. During the edge changing phase, mean (vGRFmean) and minimum forces (vGRFmin) were calculated. Mean absolute differences of the outside and the inside phase and maximum absolute differences during the edge changing phase were calculated.