Swimming is an excellent form of exercise as well as a great fitness training aid for all disciplines. Horses are able to exercise without supporting their own body weight. It builds muscle tone and improves fitness without putting pressure or strain on the back or joints. It is also advantageous to the cardio vascular system and allows horses to relax or rehabilitate without the severity of impact exercise. Horses out of work can lose muscle tone quickly but swimming can help maintain condition and physical fitness.