Fig. 5. Horizontal and vertical coordinates of the proximal end of the tarsometatarsal segment (A) and segment angle (B) in a representative bird unloaded (closed symbols) and limb-loaded (open symbols), running at 1.5 m s^-1. Horizontal coordinates from the video were corrected for tread speed and thus the total distance moved in A indicates the stride length. Data were collected at 0.004 s intervals from foot-down to the next foot-down.