Position
Stand in a ready position with your feet about shoulder-width apart, your knees and hips slightly bent, and your weight on your heels. With your upper arms pulled firmly to the side of your body, hold the dumbbells with your lower arm supine, neutral, or partially pronated, depending on which portion of the biceps you wish to target. Begin with your elbows aligned under your shoulders and slightly bent.

Technique
Contract your biceps, flex your elbows, and with your hands relaxed, begin to pull your lower arms out and up in front of your body. Pull your lower arms out and up in a natural angle from your elbow, as far as they will go, without moving your upper arms. Do not exceed the point of gravitational pull on the dumbbells. Hold, relax your hands, and continue to contract your biceps. Slowly lower your arms back to their original start position keeping tension on your biceps. Repeat.