If you’ve ever caught yourself hunching a little too far over your computer, straightening up your posture when you’re with friends, or feeling uncomfortable after a day at your desk, there’s one often-overlooked muscle you can strengthen to help you sit taller: the rear deltoids (aka rear delts).

The rear delts are one head (or section) of the deltoids (i.e., shoulder muscles), and they’re important for more than just shoulder health. Strong and functional rear delts are also essential if you want to counteract the negative effects hours at your desk or too much doomscrolling can have on your posture. However, this muscle can often be overlooked on upper body day—rear delt exercises don’t always make it into people’s strength training routines.

“I would say this head of the shoulder [muscle] is probably one of the most undertrained,” says Peloton instructor Adrian Williams. To help you add more rear delt training to your routine, we chatted with three experts who break down the benefits of training this muscle, tips on maximizing your workouts, and some of the best rear delt exercises you can do.

What Are the Rear Deltoids?

Your deltoids are triangle-shaped muscles that form the rounded outer part of your shoulders—think: the sleeves of a T-shirt. There are three distinct heads or sections of the deltoid muscles: anterior (front), medial (middle), and posterior (rear). 

The rear, or posterior, deltoid has a few different functions, but its main job is to help you reach behind your body, explains physical therapist Abigail Warner. It also plays a supporting role in stabilizing the shoulder joint. While the four rotator cuff muscles are the primary stabilizers in your shoulder, the deltoid acts almost like an assistant. “In most of the people that I see in the clinic reporting shoulder pain, the rotator cuff musculature is weak, and so the deltoid ends up doing a lot more of the job,” Warner says. This can end up causing pain or injury. 

Rear delts are also key for supporting your posture, since they help externally rotate your arms and keep your shoulders back, adds Milica McDowell, physical therapist and vice president at Gait Happens. 

The Benefits of Training Your Rear Delts

Training the rear deltoids is important for everyone, as it can help optimize the overall health of your shoulders and improve posture.

As Adrian says above, the rear deltoids tend to be undertrained compared to the other parts of the shoulder. The anterior deltoid, for example, is worked by moves you might more commonly see in a strength routine, such as the overhead press, chest press, bench press, thrusters, and even planks and push-ups. “Training your rear delts improves your shoulder balance and stability, which in turn helps reduce the risk of injury,” Adrian says. 

Because your rear delts mainly act to pull your arm backwards, training them also “enhances performance in any pull movements or exercises that you perform,” Adrian adds. That can help you, say, lift heavier during a bent-over row, but also aid other activities. Swimmers, for example, need strong and functional rear delts for an efficient freestyle, and tennis players need them to pull their racket backward and hit a powerful forehand or serve. Runners use their rear delts to power an efficient arm swing, while rowers use them to pull the handle back and finish a stroke.

Perhaps even more importantly, strong rear delts help you maintain proper posture by keeping your shoulder blades back and your arms externally rotated, McDowell says.

Finally, for those who are focused on physique, such as bodybuilders, the rear delt also functions for the “aesthetic” piece, Warner says. Training the deltoid muscle in all three parts contributes to the rounded and balanced shoulder appearance.

8 Best Rear Delt Exercises 

“Training your rear delts 2–3 times a week is a great way to isolate and focus on this muscle,” Adrian says. He suggests focusing on higher volume (i.e., more reps) and training the muscle at different angles by incorporating rear delt exercises that are performed while seated, bent over, and standing, including the eight options below.

1. Bent-Over Reverse Flys

This move is great for isolating the rear delts, but must be done with proper form to engage the muscle and avoid injury, Adrian explains. Most people likely have a dominant side, so keep an eye on your arms throughout the movement, making sure they move at the same speed and end at the same height. (This exercise is a great alternative to seated reverse pec deck flys if you don’t have access to that machine.)

2. Seated Reverse Pec Deck Flys

The great thing about this move is that the motion is very controllable, and it’s easy to add volume without worrying about your form failing, Adrian adds. Note, for this move you’ll need access to a pec deck machine found at your gym.

3. Chest-Supported Reverse Fly

This rear delt exercise, a favorite of Warner’s, uses an incline bench and dumbbells. You can also turn your wrists so your palms face your knees to work the rear delts from a slightly different angle.

4. Face Pull

This move helps balance your shoulder muscles, improves posture and overall shoulder health, and drills rotation and retraction of the shoulder blades, Adrian says. You can perform this move using the cable machine at the gym or by using a resistance band looped around a fixed point.

5. Single-Arm Row

Any variation of a row is a great rear delt exercise, Warner says. This move works best when you have a dumbbell and a bench or other elevated surface you can use to support the move. (If you don’t have anything available, you can perform a single-arm dumbbell row in a lunge position.) You’ll complete your reps on one side of your body, then repeat the movement on the other side.

6. Bent-Over Y Raise

Try this move with just your body weight, as shown, as part of a strength warm-up, or add dumbbells to increase the challenge.

7. Band Pull-Aparts

Incorporating resistance band exercises into your routine is an easy way to build strength without a lot of equipment, and is especially great for those who have limited space for a home gym. Band pull-aparts target your rear delts, as well as other stabilizing shoulder muscles.

8. Pull-Ups

The pull-up can be one of the hardest exercises to master. To modify, perform band-assisted pull-ups by looping a large looped resistance band around a pull-up bar and resting your feet or knees inside the loop.

Form Tips for Training Your Rear Delts

When doing rear delt exercises, there are a few things you need to keep in mind, according to Adrian.

How to Incorporate Rear Delt Exercises Into Your Routine 

While your rear delts might already jump into action during some of the other moves in your workout routine, Adrian suggests incorporating exercises that focus specifically on the muscle 2–3 times per week. 

If you typically do full body strength workouts, consider adding some type of rear delt “pull” exercise in each of your workouts, Warner suggests. If you follow a workout split, it might make sense to incorporate rear delt exercises into your shoulder, back, or pull workout days.

Before you get into your workout, consider utilizing resistance bands to warm up and increase blood flow to the muscles. Then don’t be afraid to include a variety of types of rear delt exercises in your routine. “I highly recommend using a variation of dumbbells, cables, or the pec deck machine in the seated position to train your rear delts,” Adrian says. 

“Focus on tension and stay consistent in your training schedule with how often you train your rear delts,” he adds. If you do, you’ll reap the many benefits of targeting this often-overlooked muscle, including better posture and overall shoulder stability.