Figure 2. The differences in the COP location between the NSP and FSP are shown for the three knee flexion angles. A) The mean %COP shifted from 41.8 ± 6.0% to 75.5 ± 8.2% (NSP vs FSP). B) The mean %COP shifted from 46.0 ± 8.3% to 79.9 ± 4.6% (NSP vs FSP). C) The mean %COP shifted from 44.8 ± 12.1% to 76.4 ± 7.5% (NSP vs FSP). * Significant difference (p < 0.05). COP, center of the foot pressure; NSP, normal squat posture; FSP, forward-shifted posture.