The BOSU resistance ball is a multi-functional resistance exercise tool that can be used for a variety of people of varying fitness levels.
The BOSU-which stands for BOth Sides Up is a half ball, half flat platform exercise equipment tool that is used in many fitness and rehab centers. The reason I like this so much is the ease of variability. Focusing on core strengthening and balance, the BOSU can be used for things as simple as lunges, single leg balance and squats double leg to enhance neuromuscular control and feedback. But you can also use it for more advanced training, exercises such as single leg squats, hops, jumps and other plyometric exercise.
I have used this for myself and to help others recover strength and balance lost from injuries or surgeries. I strongly recommend it as a variable piece or balance/core strengthening equipment