If the work is incorrect, the horse's conformation can become rough, develop thickenings and bulges in some places and hollow, weak spots in others. Develop suppleness and strength evenly on both sides of the body. Gradually shift the weight of the horse from the forehand to the hindquarters. Improve the style or expression of the horse's movement. Improve the quality of the gaits.
Most horses start out with one of two basic frames.
The first frame is when a horse carries himself with a shorter topline than underline. The horse holds his head high with his nose extended as much as 45 degrees in front of the vertical. His croup is higher than his withers and is held flat or up, causing the hind legs to trail behind the horse and the back to be hollow. Gravity, the weight of the tack and rider, and a horse's intestinal fill all contribute to a hollow back. In addition, various conformational components can predispose a horse to have a hollow back and a horse with weak or poor muscle tone will display a hollow back, especially once his muscles have become tired.