Over Gym Ball is mainly used in rehabilitation and in various exercise classes. A number of strengthening, stretching and balancing exercises can be done with a small ball. The exercise is compensatory of a slower nature, aimed at eliminating faulty body posture and muscle imbalance. Exercising with the Over Gym Ball engages the deep stabilizing muscle system - especially the muscles of the back, neck, abdomen and pelvic floor. It helps to properly strengthen the body and improve its posture.