The callused surface of the frog, bars, and sole are left undisturbed. A large majority of foot problems involve the anterior portion of the foot, he added. Mechanically reducing the pounds per square inch by attenuating the tendon pull to these structures offers a more ideal healing environment, which enhances massive sole growth, thicker walls, and a heavier, more supportive heel, according to Redden. Redden says the four point trim can be applied to any horse, regardless of its discipline. Concussion is when the hoof is rapidly brought to rest with the surface during the early stance.
Concussion includes both impact and frictional forces.
Impact is the vertical braking force of the hoof with the underlying surface. If the impact force is within normal parameters, then the force will strengthen the bones of the legs. However, if the impact of the force is more than the normal parameters, then the legs will not be able to handle the stress at all or the impact can cause damage to the limbs. The surface of the track is a vital component that affects the impact deceleration of the hoof. It has been suggested that the surface the horse is on can be manipulated to lower the injury rates in horses' limbs.