The anterior and lateral deltoids are used for the shoulder press. The anterior deltoid is the front of the shoulder, and helps raise the arms in front of the body and above the head. The lateral deltoid is the top and side of the shoulder, and helps lift the arms out and press weight above the head. The posterior deltoid is in the back and is responsible for pulling weight toward the body, or swinging the arms back. It is not activated by the shoulder press.