Stand in front of a clear open space.
Hold a ball in your hand, about the size of a tennis ball.
Walk forward whilst you throw the ball up in the air and catch it with the same hand.
Maintain your gaze on the ball at all times and allow your head to track the ball's movement.
Continue walking and tracking the movement as you throw and catch the ball in the same hand, for the prescribed duration. Repeat the exercise with the other hand.
