Medicine ball round the clock

My fave abs workout is round the clock with the medicine ball. You'll need a partner to throw the ball to you. You sit on the floor in a V-sit. This means balancing on your bottom with hands and feet off the ground. Abs activated. Then your partner throws the ball to you at different o'clock positions and you need to pass back without losing your balance. Complete two minutes then switch. Try 5 reps.