FIG. 3.

Normalized ground reaction forces in one cat (CHRONIC-1) at a walking speed of 0.4m/sec 12 weeks after grafting. The left panel shows the right and left vertical ground reaction forces over ∼10 steps. Normalized peak vertical force reached >4 N/kg for both hindlimbs during each step over that period. Panels on the right show the means and 95% confidence intervals of the vertical, fore-aft (or anteroposterior), and mediolateral forces over the stance period (0–100%). The average peak normalized vertical forces over 163 steps were 3.4 N/kg for the left hindlimb and 4.2 N/kg for the right hindlimb. Fore-aft forces were initially positive (indicating braking), until ∼40% of the stance phase, when forces turned negative (indicating propulsion). Mediolateral forces did not show the lateral push seen in able-bodied cats,^23,25,64,65 indicative of the lack of balance control in spinal animals.