Fig. 6. Representative sequence of observed force (open circles), and the calculated forces due to acceleration reaction (blue line), drag (green line) and pressure gradient (red line). The three calculated forces sum to total calculated force (black line). Note that pressure gradient force (an average of 65.7% of total force) and acceleration reaction force (32.9%) peak concurrently, while drag force (1.4%) peaks 0.7 ms later. The observed and calculated forces are in good agreement throughout the strike (R²=0.84, P<0.001).