Superhero Shoulders: Building Your Posterior Deltoid

When you ask fitness enthusiasts about their goals, many mention achieving a V-shaped upper body with strong, well-rounded shoulders.

While the front and side deltoids often get most of the focus, the rear deltoids complete your physique and elevate your gains to the next level.
Imagine having shoulders as impressive as Captain America’s – broad, strong, and perfectly sculpted. Focusing on your posterior deltoids can enhance your posture, boost your athletic performance, and help you achieve that superhero physique.

In this Muscle and Motion article, we provide a complete guide and exercises to help you develop your posterior deltoids and get those impressive shoulders!

Anatomy and functions of the deltoid

The posterior deltoid is one of the three segments of the deltoid muscle. The deltoid is a prominent, triangular-shaped muscle that drapes over the shoulder joint, giving it its rounded appearance. This muscle is crucial for a wide range of arm movements and is divided into three distinct parts: the anterior deltoid, the middle deltoid, and the posterior deltoid.

Origins (proximal attachment):

• Anterior deltoid: Lateral third of the clavicle
• Middle deltoid: Superior surface of the acromion
• Posterior deltoid: Spine of the scapula

Insertion (distal attachment):

• All three parts converge to insert at the deltoid tuberosity on the humerus.

Functions of the posterior deltoid

To effectively build well-rounded shoulders and enhance the size of your posterior deltoids, it’s important to understand the primary movements performed by this muscle:

1. Shoulder extension
2. Horizontal abduction
3. External rotation
   

The key principle for exercise selection

When planning a workout routine for the posterior deltoid, it’s important to understand whether you should start with compound or isolation exercises. Both types of exercises have their benefits and should be strategically included in your training plan. The following exercises are categorized by the specific movements of the posterior deltoid, including compound and isolation exercises:

1. Shoulder extension

Bent-over row 

The bent-over row is typically used to build and strengthen the upper back and shoulder extension muscles. However, to stabilize this body position, assistance from the lower back, core, and entire posterior chain muscles is required.

• How to perform: 

1. Hinge forward and begin the movement by driving the elbows behind the body while retracting the shoulder blades.
2. Pull the kettlebell towards your belly button and then slowly lower the kettlebell back to the starting position under control. 
3. Repeat for the desired number of repetitions. ‎

Lying barbell row

Unlike the bent-over war row, this exercise does not require as much stability from the posterior chain muscle and allows you to focus solely on shoulder extension.

• How to perform: 

1. Lie face down on an incline bench and grasp the barbell with your hands, palm facing backward. 
2. Pull the bar toward your chest with your elbows pointing upwards. 
3. Slowly lower the bar back to the starting position.
4. Repeat for the required number of repetitions.

2. Horizontal abduction

Rear row

The rear row strengthens the posterior deltoid using bodyweight resistance.

• How to perform:

1. Set the bar around waist height. The lower the bar, the more difficult the movement becomes. ‎ 
2. Hold the bar with both hands slightly wider than shoulder-width so you’ll be able to row effectively with elbows at shoulder height. 
3. Keep your body as straight as possible. ‎
4. Pull yourself up to the bar until your chest touches the bar. 
5. Your elbows should be pointing outward during the entire movement. 
6. Slowly return to the starting position and repeat.

Rear row fly

The rear row fly is an isolation exercise performed in the transverse plane, specifically targeting the posterior deltoid. 

• How to perform:

1. Lie prone on a slightly inclined bench and grab a dumbbell in each hand. 
2. Horizontally abduct your shoulders while keeping your elbows straight the entire time.
3. To emphasize the load on the posterior deltoid, minimize scapular movement.
4. Go back to the starting position and repeat.

3. External rotation

Side-lying shoulder external rotation

This exercise strengthens the external rotators, emphasizing the posterior deltoid using a dumbbell. Lying on your side ensures gravity resists the movement, with peak resistance at the start.

• How to perform: 

1. Lie on your side, holding a weight in the upper hand.
2. Keep your elbow bent at 90 degrees and pressed against your body.
3. Raise the weight by rotating your shoulder outward, lifting the dumbbell away from your abdomen.
4. Lower the weight back to the starting position with control.
5. Repeat for the desired number of repetitions.

Shoulder external rotation (mini band)

This exercise targets the external rotators, focusing on the posterior deltoid using a resistance band. The band ensures maximal resistance when your shoulders are fully externally rotated, and the posterior deltoid is shortened.

• How to perform: 

1. Stand straight and place a mini band around your forearms just above your wrists.
2. Bend your elbows upward to 90 degrees and hold your upper arms at the sides of the body.
3. Rotate your shoulders outwards so your hands will point to different sides while keeping your elbows close to your body.
4. Slowly bring your hands back to the starting position and repeat.

4. Movement combination

Face pulls with external rotation

Unlike the previous exercises, this one combines external rotation with horizontal abduction, engaging the posterior deltoid across multiple planes of motion. This combination results in a higher load on the posterior deltoid.

• How to perform: 

1. Use a cable machine with a rope handle or similar attachment. Position the cable at face height.
2. Stand with feet shoulder-width apart and grab the handles with palms facing each other.
3. Pull the cable towards your face, keeping your elbows high. Rotate your shoulders so palms face your face, forming a “W” shape with your arms.
4. Slowly return to the starting position and repeat for the desired number of repetitions.

In summary, building strong posterior deltoids is essential for achieving well-rounded shoulders and a superhero-like physique. Often overlooked in favor of the anterior and middle deltoids, the posterior deltoids can significantly elevate your shoulder gains and sculpt impressive, balanced shoulders.

This comprehensive Muscle and Motion guide outlines the anatomy and functions of the deltoid muscle, emphasizing the importance of targeting the posterior segment. It provides detailed exercises categorized by key movements—shoulder extension, horizontal abduction, and external rotation—to help you effectively train and develop your posterior deltoids. 

Check out our Strength Training App for countless additional shoulder and posterior deltoid exercises.

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At Muscle and Motion, we believe that knowledge is power, and understanding the ‘why’ behind any exercise is essential for your long-term success.
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