Create lean, well defined , sexy shoulders.

Target the three heads of your deltoid muscles to create sexy, curvy shoulders.

WHY IT WORKS
Located at the tops of your arms, your deltoid muscles have three distinct heads: the anterior (front), lateral (side) and posterior (rear), which come together to form a triangle. It's important to work all three heads of the deltoids to develop an even, rounded contour, says this month's featured trainer, Irene McCormick. "Most women tend to focus on what they see in the mirror and neglect their rear shoulders," McCormick says. With her trio of exercises, shown here, you can sculpt the front and sides of your shoulders while also firming up the accessory muscles that underlie the soft, underdeveloped area under the back part of your bra strap.

MUSCLE MECHANICS
The three exercises featured on this page are designed to target your deltoid muscles. While the three heads of the deltoids have different origins, they all attach on your upper arm. The anterior head originates at your collarbone. Its primary role is to raise your arm up and forward and rotate it inward. The posterior head attaches to your shoulder blade and acts primarily to move your arm backward and rotate it outward. The lateral head, which is located between the other two heads, primarily works to lift your arm out to the side as well as to assist the anterior and posterior heads in their movements.

1. Overhead Press

Strengthens middle and anterior deltoids and trapezius (upper back)

2. Incline Rear Fly

Strengthens posterior deltoids

3. Shoulder Raise

Strengthens anterior and lateral deltoids