Stand holding a ball in one hand.
Lift your hand out to the side to shoulder level and bend your elbow to 90 degrees so that your fingers are pointing forward, and your palm is facing down.
Drop the ball and immediately catch it before it falls.
Repeat this until you get tired or for as long as advised.
To increase the difficulty of the exercise you can move your arm so that it is vertical, and your hand is pointing towards the ceiling, and return to catch the ball.
