Exercise Ball

Exercise Ball: "Exercise balls are effective for toning the trunk muscles - the abdominals, lower back, and buttocks. The body automatically engages these muscles to keep balance so the muscles become stronger and better shaped. First used by physical therapists for low back pain, the exercise ball is now standard exercise equipment for stretching, strengthening, and toning core body muscles. If this is all new, get an Exercise Ball with Workout DVD. There are guidelines for determining the right diameter exercise ball for your height and weight."