A medicine ball is a weighted ball with a diameter of about a shoulder-width. The size of a medicine ball is approximately 350 mm (13.7 in), often used for rehabilitation and strength training. The medicine ball also serves an important role in the field of sports medicine to improve strength and neuromuscular coordination. It is distinct from the inflated exercise ball, which is much lighter and larger which is up to 37 in (95 cm) in diameter.