You will need an assistant for this exercise.
Lie on your back on an exercise ball with your knees bent and feet flat on the floor.
Push your hips up and lift your arm as high over your head as you are able with your palm facing towards the ceiling.
When ready, your assistant will drop a ball into your hand from a small height above you.
Ensure you follow the ball with your eyes as you catch it and throw it back to your partner.
When ready, your partner can change the position and frequency of the drop to increase the difficulty.
