Body Solid Tools Exercise Balls. Get rolling on your Core Strength and Stability. Body Solid Tools Exercise Balls provide a simple but effective way to focus on core strength and stability. Physical therapists have used exercise balls for years to strengthen the abs and back while improving balance and stability. Body Solid"s anti-burst exercise balls are sized right to fit your height and are equally suitable for light commercial and home use. Body Solid Tools. A good fit for your life. A great fit for your space.