FPPA of the knee was measured as the angle subtended between the line from the markers on the proximal thigh to the knee joint and the line from the knee joint to the ankle, and was measured at the frame which corresponded with the point of maximum knee flexion (Willson et al., 2006), as shown in Fig. 1. Point of maximum knee flexion was determined as the lowest point of the movement. Each angle was digitised manually by the same experimenter using the Quintic software package. Positive FPPA values reflected knee valgus, excursion of the knee towards the midline of the body so the knee marker was medial to a line between the ankle and thigh markers. Negative FPPA values reflected knee varus. The average FPPA from 3 trials was used for analysis. Between-session reliability of this method has been established using intraclass correlation coefficients and range from 0.72 to 0.91 (Munro, Herrington, & Carolan, 2012).