The 2D-Cam and 2D-Mot techniques resulted in similar stance phase valgus patterns for each of the three movement
conditions, but frontal plane knee angles were on average larger than corresponding 3D knee valgus angles (table 2).
The time of the rotation peak was also later for the 2D techniques. Mean male and female data are presented for
side stepping as a sample (fig 4). Approach velocities were similar in the side step (4.85 (0.17) m/s), side jump (4.81
(0.26) m/s), and shuttle run (4.88 (0.31) m/s) conditions. This suggests that the approach speed was not responsible for
differences between movements and sexes. Mean RMS errors of 1.7 ̊, 1.5 ̊, and 16.0 ̊were found for 2D-Cam and 2D-Mot peak angle data comparisons for side step,side jump, and shuttle run respectively. RMS errors were smaller than group mean between-trial variations observed in peak 2D-Mot frontal plane knee angles for both side step(3.3 (1.1) ̊) and side jump (3.3 (1.7) ̊). RMS errors werenoticeably larger than between-trial variations, however, forthe shuttle run (5.4 (2.6)
).Between subjects, 2D-Cam and 3D peak angle mea-sures correlated well for the side jump (r2= 0.64) and side step (
r2= 0.58) (fig 5). In each case, the slope of the linear regression (side jump = 0.32; side step = 0.4) was signi-ficantly (p,
0.05) different from zero. Correlations between these data for shuttle run movements yielded much lower r2 values (
r2= 0.04) and a slope (0.07) that was not significantly different from zer