Fitness balls are known by a number of different names including Swiss ball, exercise ball, gym ball, sports ball, fit ball, stability ball, therapy ball, yoga ball, balance ball, or body ball. These balls are light weight, are constructed of an elastic material such as rubber or a polymer, and when inflated with air are usually around 20 to 30 inches in diameter. Fitness balls are used in exercise and physical therapy. Fitness balls should not be confused with medicine balls which are smaller, filled with a packing material rather than air, and heavier.
When a person uses a fitness ball, their body must continually compensate for the instability of the ball and they thereby use many more muscles than in conventional exercise. The abdominal and back muscles particularly benefit from fitness ball exercise. Also, the firmer (more inflated) the ball is the more difficult the exercise will be. Some examples of fitness ball exercises are:
squat and reach
plank
plank with forward lean
reverse crunch
abdominal sit-back
bridge
bridge with heel dig
abdominal ball rise
abdominal ball rotation
side exercise