Stand with your feet just wider than shoulder-width apart. Bend your knees and hips, with your trunk between 45 and 75 degrees in relation to the floor. Maintain a natural arch in your back. Keep the weight over your ankles. Hold the dumbbells perpendicular to your body, your arms straight down, and your elbows pointed out and slightly bent. Pull and hold your shoulder blades tightly together throughout the exercise. Begin with your arms slightly out so there is some degree of gravitational pull on the dumbbells.
With one arm remaining in the start position, contract the posterior deltoids of your other shoulder. Bend your elbow and pull your arm out and up until your upper arm is approximately parallel to the floor, forming about a 90-degree angle. Hold and continue to contract your posterior deltoids. Keep your arm relaxed, elbow pointing up, and scapulae retracted. Slowly lower your arm back to its original start position, keeping your scapulae retracted and tension on your posterior deltoids. Repeat using your other arm.