Hold a dumbbell in each hand. With a slight bend in your knees, lean your torso forward, keeping your spine neutral, until you're at roughly a 45 degree angle. Your arms should be extended toward the floor. This is your start position. Keeping your torso stationary and maintaining a slight bend in your elbows at all times, pull the dumbbells out and up to your sides. Continue until they are parallel to the floor. Squeeze your rear delts as you do and exhale. Hold for a count of one before returning to the start position. Inhale as you do so. Repeat for the required number of reps (or time).