Stand with your feet hip-width apart holding a 12- or 15lb dumbbell in your right hand. Lift your right leg slightly off the ground behind you.
Keep your right leg off the ground, squat down a few inches with your left leg. Bend your right arm and pull the dumbbell up to waist level. Then lower the dumbbell and straighten your left leg. Do 15 reps, then switch the dumbbell to your left hand and repeat the move with your right leg. Work up to three sets.