EXERCISE 13.
Hold the right hand edgewise before you, the thumb towards the chest. Have the fingers closed tightly together and bring the thumb firmly against the first finger. With a sharp, quick action, open the thumb away from the finger, so that it points over your shoulder; at the same time bending the entire hand sideways at the wrist, bringing the thumb still nearer the shoulder. The movement must be quite snappy to get the desired effect. Repeat twelve times.
Perform this exercise twelve times with the left hand.