Forelimb hoof landing velocities in treadmill trotting and galloping horses

Forelimb injury has been attributed to many factors. A key component to understanding the injury mechanisms is an accurate knowledge of hoof landing velocity and the ensuing kinematics of hoof strike. Five seconds of sagittal plane high-speed video were collected at 500 Hz from the right side of 22 mixed breed/grade horses while trotting and galloping on a treadmill. A reflective marker was placed on the center of the medial side of the hoof of the left forelimb with three hoof strikes digitized and averaged. Nine led with this limb during the gallop while 13 led with the right limb (treadmill speed trot = 4.4 m/s, gallop = 10.1 m/s). Differences were assessed at p < 0.05. Vertical hoof velocities at impact were significantly greater at gallop (-3.7+/-0.9 m/s) relative to trot (-1.9+/-0.5 m/s). No significant differences in vertical hoof velocity were found between lead and trail limb at either speed. Horizontal hoof velocity at impact was significantly greater in the lead limb (-7.4+/-1.4 m/s) relative to the trail limb (-5.6+/-1.5 m/s) at gallop as well as both being significantly greater than during the trot (-2.5+/-0.7 m/s). These results provide a starting point for both computer and mechanical models simulating hoof strike with the goal of reducing equine injuries.