A situation seen when a horse is unwilling or unable to place the heels on the ground and loads the toe only. Typically caused by a painful condition in the heels (e.g. a hoof abscess) or on the plantar/palmar aspect of the distal limb (e.g. a tenosynovitis of the digital flexor tendon sheath). Occasionally caused by congenital or aquired flexor tendon contractions such as a severe club foot.