The Fitness Ball is the large exercise ball that you will probably recognise from gyms, exercise videos and the Osteopaths’/ Physiotherapists’ clinics. Similarly to the small Over Ball, the Fitness Ball can be used in a variety of ways adding resistance, creating instability, supporting the body or providing tactile feedback. It can also be used as a very big, yet only moderately heavy weight to increase difficulty and range of motion. A primary benefit of using the Fitness Ball is the need to engage the core muscles in order to remain balanced during the exercise, which is a primary goal of any Pilates class. Fitness Balls are sometimes called Stability balls, Swiss balls or Pilates balls. They come in many different diameters so please make sure to purchase the size appropriate to your height.