This is a lovely class incorporating the ball into many of the Mat Pilates exercises. The ball is so much fun, it can add challenge and depth to a well known movement such as the pilates 100's so I hope you enjoy the different dynamic this class with the ball offers you. If your back hurts when using the ball, please stop. Think about the placement of the ball and perhaps the ball needs more air or deflating slightly. Play around with those 2 options. If there is still back pain, then omit the ball and focus on building your core strength and control without the ball and build to the ball workouts later.