Stand up straight with your arms by your sides.
Bend both elbows to 90 degrees so that your forearms point directly forwards.
Lift your upper arms away from your sides a little and keep them in this position.
Keeping your neck long and your shoulder blades relaxed, simultaneously rotate both forearms outwards as far as you can go comfortably.
Control the movement as you bring both forearms back in, and then repeat the movement.
