What is the Live Up BOSU Ball? The Live Up BOSU ball is a widely used fitness-training device. Consisting of an inflated rubber hemisphere attached to a rigid platform, it is also referred to as the "blue half-ball", because it looks like a stability ball cut in half. It also comes with a pair of Resistance Bands that can be attached to the BOSU Ball for resistance training. The BOSU ball can be used and incorporated into a wide range of exercises and fitness routines. Used correctly the BOSU ball will strengthen the entire body and by incorporating cardio moves can help to raise your heart rate. The BOSU ball is an excellent tool for losing fat and toning your body by improving your core strength and developing overall balance and muscle strength.