You'll need two different dumb-bells for this exercise - one light-to-medium and one heavy. Place one knee and your non-working hand on a flat bench for support, then bend forwards at the hips and grasp the heavy dumb-bell in your free hand.

Pull the dumb-bell up to your abdomen.

Do 12 reps, then immediately grab the lighter dumb-bell and raise your upper arm until it's parallel to the floor and your elbow is bent 90.

Keeping your upper arm stationary, slowly extend the dumb-bell up and out behind you. Pause when the arm is extended, then return to the starting position. Do 12 reps. Repeat the two exercises on your other side.