Contracted heels is a condition in which the inner and outer buttresses of the foot becomes narrower than normal, with potential atrophy of the frog. It usually occurs in the front feet, but can also affect the back feet of the horse. A horse's foot is considered contracted if the frog width is less than two-thirds the frog length.
The condition occurs in horses of all ages. In younger horses, it can be congenital or acquired. Horses can develop contacted heels as a result of genetics or through environmental or managerial factors such as long term stall rest, insufficient exercise, excessive moisture, disproportionate load balance on the frog and heel, and the result of improper shoeing. If the farrier removes the frog during each hoot trimming, the lack of frog pressure can cause contracted heels. Horses having long toe/low heels or overgrown hooves can also cause contracted heels. Long toes decrease the expansion of the hoof when the foot hits the ground, which causes the heels to contract.