The posterior deltoids help with many pulling movements and stabilize the shoulder joints. Rowing, pull-ups, and other exercises can help to improve posterior deltoid strength.

You need strong shoulders to be able to lift, push, and pull without injury.

Gaining shoulder strength requires working many muscles from different angles. The front of your shoulder — the anterior deltoid, in particular — tends to be somewhat dominant in many exercises and everyday movements.

For example, the anterior deltoid is involved in raising your arms in front of you and also aids in pressing movements such as the bench press.

But strengthening the middle and posterior deltoids is important too.

The middle deltoid raises your arms out to the sides, and the posterior deltoid extends your humerus behind you, in movements such as bringing your arm backward when walking or when pulling a lawn mower cord (1).

The posterior deltoid also aids in externally rotating your shoulders, as you do when you rotate your hands out to make the gesture for “I don’t know” (1).

These muscles all work together to keep your shoulders stable for daily functions like carrying heavy grocery bags with your arms down at your sides. But the posterior deltoids can be tricky to target in the gym.

These 6 moves will help you gain rear deltoid strength and stronger shoulders overall. Try adding a couple of these exercises to your regular strength workouts each week.

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The days you work your shoulders and back are the perfect time to add this move. Try to finish off back day with this multi-joint movement that will help you gain posterior deltoid strength.

Equipment needed: dumbbell and bench

Muscles worked: rear deltoids, back, biceps, transverse abdominals

How to do it:

  1. Place your left knee and left hand on the bench. Keep your left elbow straight.
  2. Extend your right leg slightly behind you, keeping your foot on the floor for support. Keep your back flat and spine neutral.
  3. Hold a medium to heavy dumbbell in your right hand, with your arm reaching down toward the floor.
  4. Bend your right elbow, pulling it up and back so your upper arm is roughly in line with your lower chest.
  5. Squeeze your shoulder blades together at the top of the movement.
  6. Lower the weight with control.
  7. Repeat on 1 side for 10–12 reps before switching to the other arm. Work up to 3 sets.

Pro tip:

  • Try to keep your trunk stable and don’t rotate it during the movement. If you can’t keep your trunk stable, either decrease the weight or end the set and rest before your next set.

When doing a long-arm lateral movement, start with a lighter weight. You can work up to a heavier weight as you get stronger.

Starting a move like this with a heavy weight can set you up for injury. But don’t worry — a lighter weight will still provide a safe way to build strength.

Equipment needed: a pair of light to medium dumbbells

Muscles worked: posterior deltoids, middle deltoids, rhomboids, middle trapezius

How to do it:

  1. Hold a pair of dumbbells, keeping your palms facing each other.
  2. Stand with feet shoulder-width apart, slightly bend your knees, and bend forward at the hips, keeping your back straight. Your elbows should be soft, and the weights should be together below your chest.
  3. Raise your arms up and out, as if spreading your wings, until they’re parallel to the floor.
  4. Squeeze your shoulder blades at the top of the movement.
  5. Lower the weights back to the starting position, slowly and with control.
  6. The weights should be light enough to do 10–12 reps. Work up to 2–3 sets.

Pro tip:

  • Aim to keep your head in line with your trunk during the exercise.

This move is a great way to mix up your shoulder training, but it does require the use of some gym equipment. Changing the angles of your muscle training can really target your deltoids in a way they aren’t used to. This will help you gain strength.

Equipment needed: cable machine with a double-handled rope attachment

Muscles worked: rear and middle deltoids, trapezius, rhomboids

How to do it:

  1. Stand with your feet hip-width apart, facing the cable machine.
  2. Adjust the cable attachment to about chest height, and then attach the rope handle to it.
  3. Stand with feet hip-with apart and step back so your arms are reaching in front of
  4. Pull the ropes toward you, pulling apart as you go. Your elbows should stay up high to help target those deltoids.
  5. Slowly and with control, extend your elbows back out to the starting position.
  6. The weight should be light enough to do 10–12 reps. Work up to 2–3 sets.

Pro tips:

  • When pulling the rope apart and toward your chest, bend your elbows 45–90 degrees away from your sides.
  • If you experience pain or stiffness with your elbows 90 degrees away from your sides (parallel to your shoulders), lower them to your comfort level.
  • Keep your head up, looking straight ahead, and keep your torso tall so you don’t arch your back.
  • You can also perform this exercise with a resistance band anchored in front of you.

There’s actually a machine at your local gym designed to work the posterior deltoid muscles. This really makes it easy to isolate those muscles safely and in a challenging way.

Equipment needed: rear deltoid machine

Muscles worked: rear deltoids, middle trapezius, rhomboids

How to do it:

  1. Sit on the machine, facing the pad. You’ll appear to be sitting on it backward, but for this exercise, you’re positioned just right. Adjust the seat height so the handles in front of you are level with your shoulders.
  2. Holding the handles, either with palms down or palms facing each other, press your arms back, keeping them straight or slightly bent.
  3. Squeeze your shoulder blades together, like a set of elevator doors.
  4. Hold here for 2 seconds, then return to the starting position with your hands in front of you. Do this slowly and with control.
  5. Do 10–12 reps.

Pro tip:

  • Keep your chest against the pad and try not to arch your back.

Pullups are a very effective exercise movement, but most people don’t have the upper body strength to perform one without a little help. This move works not only your posterior deltoids but also your lats, trapezius, and biceps.

Equipment needed: assisted pullup machine

Muscles worked: latissimus dorsi, deltoids, middle and lower trapezius, biceps

How to do it:

  1. Adjust the weight deduction on the side of the machine. Choose the correct amount and set.
  2. Climb onto the knee pad and push it down until it’s low enough for you to place both knees on. Your knees should be hip-width apart.
  3. Hold the outer handles above you, keeping your palms facing away from the center.
  4. Extend your arms and lower yourself to the starting position.
  5. Pull your body up until your chin is level with or above the handles.
  6. Hold the position for a few seconds, then lower yourself down with control. Focus on keeping your shoulder blades engaged. They should be pressed back and down.
  7. Start with 6–8 reps and work up to 10–12 reps.

Pro tips:

  • Start with a weight that’s light enough to make the exercise challenging but still allows you to complete the movement successfully with good form.
  • If you can complete any reps without the assistance (using good form), you can start without the assistance and transition to using it when you can’t complete any more reps.

This exercise focuses on the external rotation motion that the rear deltoid performs. It also targets some of the rotator cuff muscles (infraspinatus and teres minor).

Equipment needed: towel, dumbbell.

Muscles worked: rear deltoid, rotator cuff, middle trapezius, rhomboids (2)

How to do it:

  1. Lie on your side, holding a light dumbbell.
  2. Place your upper arm on your side with your elbow bent at 90 degrees. If you have broad shoulders, place a towel roll just between your upper arm and your torso.
  3. Rotate your arm on your torso as far as you can without letting your upper arm drift off your body. Hold for 1–2 seconds, and then slowly lower it back to the starting position. Do 10–12 reps.

Pro tips:

  • Keep your upper arm resting on your body and let it rotate like a door hinge.
  • Keep your body stable and try not to rotate your torso back. Work with the range of motion available in your shoulders instead of getting more movement from your torso.

The posterior, or rear, delts are important shoulder muscles used in many pulling movements, and they’re important shoulder stabilizers as well. It makes sense to strengthen them for healthy shoulder mobility.

As with any exercise routine, it’s a good idea to check with a healthcare professional before trying these exercises for the first time. It’s also a good idea to work with a qualified trainer to make sure you are safely using the machines to your benefit.

If you’re working on developing your shoulders in a balanced way, adding these moves to your regular shoulder workouts will help balance out the heavier, front-loaded movements often seen in other common gym exercises.