Stand with the feet shoulder-width apart and clench your fists, holding your arms by your sides.
Clench your fists and bring them up to shoulder height, knuckles upward, elbows at your sides. Open your fists.
Time it so the breath runs out as the arms reach full stretch, then breathe in through your nose and at the same time, start to clench your fists and bend your elbows so that they are again near your shoulders, elbows down.