Gym Balls (also know as Swiss Balls and Core Stability Balls) are very useful in making basic exercises harder and improving your core stability. Gym Ball exercises aren’t restricted to core stability improvement, they can be used to perform squats or exercises to improve your bum. If you haven’t already you should try doing basic exercises such as a bicep curl sitting on a gym ball and see the difference, when you have mastered this try moving on to doing a bicep curl while kneeling on the gym ball.
Gym / Swiss Ball Exercises
Exercise Balls are good for working on stability and can feature as a progression for the majority of exercises.