Fig. 4. Vertical displacements of the fore quarters, hind quarters and center of mass versus time for one typical walking stride at 0.8 m s^–1. The relative magnitudes and the timing of the actual displacement data (A) corresponded to the compass gait prediction (B). The similarities suggest that the fore and hind quarters actually vault over their support limbs like independent bipeds. The sharp transition points in the compass gait prediction (B) correspond to an instantaneous transfer from left to right limbs at the middle of double support. However, in a dog (A), this transition is smooth because it occurs over the entire period of double support. The dog's leg length and contact time were 0.54 m and 0.696 s, respectively, for the fore limbs and 0.45 m and 0.629 s, respectively, for the hind limbs. (C) The dog's actual footfall pattern from A; LH, left hind limb; LF, left fore limb; RH, right hind limb; RF, right fore limb.