Shoeing with wedges is all about redistributing the forces among the force bearing structures of the hoof. This statement by Jeff Thomason, of the University of Guelph, encapsulates the purpose of wedges in farriery.

Since wedges — heel, toe or side — are commonly used to change the hoof angle in shoeing, it’s a good idea to take a look at the impact of these tools on the structure and function of the foot. Changing the angle of the foot can have significant effects on the anatomy of the foot and the forces placed upon the structures of the foot.

To understand how wedging affects the hoof and the horse, we need to take a brief look at the phases of the stride and some basics of equine biomechanics.

Phases Of The Stride

Impact. As the hoof hits the ground, hoof velocity quickly slows, coming to a stop. This deceleration depends upon the ground surface and the foot velocity.

Mid-stance. During mid-stance, the limb is loaded distal-proximal (hoof-toward body) and the force is transferred through the muscles and tendons of the limb.

Breakover. This transition between the stance phase and the next stride occurs as the center of force shifts toward the toe. As the foot rotates, the toe pushes into the ground on a soft surface or slips slightly backward on a hard one.