The reebok mens training 75cm gym ball is a very useful piece of fitness equipment that allows users to do a number of effective exercises to work on improving core strength flexibility balance posture and general fitness possible exercises include tricep dips lower ab crunches the plank shoulder curls and press and side squats plus a workout dvd is supplied with the swiss ball to help you get started anti burst technology means if the exercise ball gets punctured it will deflate in a