Rear Delt Flys: Muscles Worked, How To Do and Form

If you want to build a bigger and stronger rear delt, then you must add a rear delt fly to your shoulder workout routine. 

Why are rear delt flys so vital? The rear delt flys are the best exercise for targeting your upper back muscles and shoulder muscles, particularly the posterior deltoids, or rear deltoids (on the backside of your shoulders).

It helps you hone in on the small muscles of the rear delt by using a full range of motion, which will explore the growth of your shoulder muscles.

In this beginner guide, we will explore the following:

• What is Rear Delt Fly
• Muscles Worked During Dumbbell Rear Delt Fly
• How To Do Dumbbell Rear Delt Fly Properly
• Best Variations
• Benefits of Rear Delt Fly
• FAQs

What is Rear Delt Flys

The rear delt fly, also known as the bent over rear delt fly, is a great shoulder exercise to assist you in building a rear delt muscles. Many lifters utilize the rear delt fly to target the rear delts, an often lagging muscle for many lifters alike.

While many shoulder exercises, such as overhead presses and lateral raises, work the front and side deltoids, on the other side, rear delt fly trains the rear deltoids. It helps you build strength, stability, and size in your shoulders.

Strengthening the rear delts using the bent-over rear delt fly can improve posture and increase strength on other lifts.

There are many variations of rear delt flys that you can add to your workout routine, and each has its own unique benefits.

• Dumbbell Rear Delt Fly: Enhances shoulder stability with free weights.
• Machine Rear Fly: Targets rear deltoids with controlled resistance.
• Cable Rear Delt Fly: Constant tension for efficient muscle activation.
• Incline Bench Rear Dumbbell Fly: Increases stretch and contraction for rear delt development.
• One-Arm Rear Delt Cable Fly: Improves symmetry and targets rear deltoid isolation.
• Resistance Bands Reverse Fly: Portable option for rear delt training.
• Lying Reverse Fly: Isolates rear deltoids for targeted growth.

Rear Delt Fly Muscles Worked

• The rear delt flys primarily work the rear delt.
• A handful of other muscles worked or stabilizer muscles, including your Lateral deltoid, trapezius, rhomboids, infraspinatus, teres minor, and teres major.
• The standing rear delt fly involves several synergist muscles, including the oblique and core.

• Rear Delt: It lifts weights or resistance laterally away from the body, making it the main muscle involved in this movement.
• Trapezius: The upper and middle fibers of the trapezius help stabilize the shoulders during the exercise.
• Rhomboids: These muscles located between the shoulder blades assist in shoulder retraction.
• Rotator Cuff Muscles: The infraspinatus and teres minor play a role in shoulder external rotation, synergistically supporting the rear deltoids.
• Posterior Serratus: helps stabilize the scapula during the exercise.
• Core and Abs: Help to stabilize the body.

How To Do Rear Delt Fly Properly

1. Stand with your feet shoulder-width apart, and hold a dumbbell in each hand.
2. Hold the dumbbells with a neutral grip (palms facing each other) and let your arms hang naturally in front of your body.
3. Bend forward at the hips and maintain a flat back. Your torso should be almost parallel to the ground.
4. Keep your arms slightly bent. Lift the dumbbells laterally away from your body and squeeze your shoulder blades together.
5. Lift the dumbbells to shoulder height or slightly higher to ensure your arms are parallel to the ground at the movement’s top.
6. Lower the dumbbells back to the starting position in a controlled manner.
7. Inhale as you lower the weights, and exhale as you lift them.
8. Do 10–15 repetitions per set. Perform 3–4 sets with a short rest period in between.

Proper Form And Technique

• Avoid using excessive momentum or swinging your body to lift the weight. Focus on using your rear delt to control the movement.
• Maintain a neutral spine and avoid arching your back or rounding your shoulders.
• A slow controlled descent will increase time under tension, leading to more effective sets, and less risk of injury.
• Inhale as you lower the weights and exhale as you lift them, coordinating your breathing with the movement.
• You should focus on the contraction of the rear delt at the top of the movement.
• Always select a weight that gives you full control of your body.
• Incorporate proper warm-ups, rest, and nutrition into your exercise program.
• Rest for 24 to 48 hours before training the same muscle groups to allow sufficient recovery.
• Perform this exercise in a slow, controlled manner for best results.
• Don’t go heavy. Choose a lighter weight and focus on perfecting your form.
• Select sets and rep range according to your fitness level. For muscle growth, it is best to do around 6–12 reps per set.

Best Variations of Rear Delt Fly

Doing different versions of the rear delt fly exercise can be helpful.

• Firstly, by changing up the angle of the movement or the type of equipment used, you can activate different muscle fibers in the rear deltoids and prevent plateauing. This can result in increased strength and muscle growth.
• Secondly, varying your exercise routine can help prevent boredom and keep your workouts interesting and challenging.
• Lastly, using different versions of the rear delt fly can help prevent injury by ensuring you are working all areas of the muscle group rather than just one.

1. Seated Dumbbell Rear Delt Fly

Dumbbell rear delt fly is an excellent isolation exercise that specifically works on the rear deltoid muscles. In this version, you do the movement while sitting, which gives you more support and stability during the workout.

Therefore, when you’re seated, it’s easier to isolate your rear delts and minimize the involvement of other muscle groups.

How To Do

1. Sit at the end of a bench with a pair of dumbbells.
2. Bend forward and let the dumbbells hang on your sides.
3. Keep your neck relaxed and avoid straining it during the exercise.
4. Lift the weights on your sides to a higher level than your shoulders.
5. Now lower the dumbbells back to your sides.
6. Do the movement slowly and with control.

2. Machine Rear Delt Fly

The machine rear delt fly (the reverse pec deck fly), is a simple yet effective exercise that increases deltoid muscle definition and strength.

The pec deck rear delt machine fly targets your upper back muscles and shoulder muscles, particularly the rear deltoids, (backside of your shoulders), Traps and rhomboids.

This machine also offers several technical adjustments to the grip. Trajectory and range of motion to help isolate the posterior deltoid.

How To Do

1. Adjust the seat height and machine handles to align with your shoulder height.
2. Sit facing the machine with your chest against the backrest.
3. Grab the handles in front with your arms stretched out at shoulder level.
4. Maintain a slight bend in your elbows and a neutral wrist position
5. Pull the handles back in an arc as far as possible and keep your elbows high and arms parallel to the floor.
6. Return the handles to the start position directly in front.

3. Cable Rear Delt Fly

A rear delt cable fly provides constant tension on the muscle. Unlike dumbbell raises, where the resistance changes during the lift, the cable pulley has a constant resistance throughout the lift.

You can easily adjust the resistance with cables to match your strength level. This makes it a great option for beginners and experienced lifters alike.

How To Do

1. Grab the handles attached to two low pulleys (left-side handle in right hand, right-side handle in left hand).
2. Stand in the middle, then bend forward at the waist with the back straight and parallel to the floor.
3. Raise your hands upward in an arc to shoulder level
4. Lower the handles back down to the start position, your right hand directly in front of the left ankle and your left hand in front of the right ankle.

4. Incline Bench Rear Delt Dumbbell fly

The incline bench delt dumbbell fly makes the rear deltoids stretch and contract more. You get a killer stretch at the bottom of the movement. Trust me, your rear delts will feel this one.

That incline keeps your body locked in. No wiggling, no using your back. It’s all rear delts.

How To Do

1. Set your bench to about a 30-45 degree incline. Not too steep, not too flat.
2. Grab your dumbbells and lie face down on the bench.
3. Let the dumbbells hang straight down. Arms should be perpendicular to the floor.
4. Keep a slight bend in your elbows and raise those arms out to the sides.
5. Squeeze those rear delts at the top like you’re trying to pinch a penny between your shoulder blades.
6. Lower the weights back down slowly.

5. Side-Lying Rear Delt Dumbbell Fly

It’s a great shoulder workout that targets the rear delts. It is a great unilateral exercise used to target a smaller and often lagging muscle group. Instead of lying on the floor, you can lie on a bench.

By lying on your side, you minimize the involvement of other muscles. This means your rear delts get more focus and work harder.

The side-lying position relieves pressure on your lower back, making it a safer option for people with back issues.

How To Do

1. Lie on the floor on your right side, and grasp the dumbbell with your left hand using a neutral grip (palm facing downward).
2. Exhale as you raise the dumbbell from the floor until it is almost vertical. Hold for a count of two.
3. Inhale as you reverse the movement and lower the dumbbell towards the starting position, stopping before the dumbbell touches the floor.
4. Repeat for the desired number of repetitions.
5. Repeat the exercise on the opposite side with your right arm.

6. Lying Rear Delt Cable Fly

The lying reverse fly is the perfect exercise to hit the rear delts. Completing this exercise in a supine position on your back lets you focus purely on contracting your rear delts to pull the cables down to the sides.

It’s important to keep your arms perpendicular to your trunk to reduce the chances of your lats helping to complete the exercise.

How To Do

1. Position a flat bench between two high pulleys.
2. Lie supine (on your back) and hold the pulley handles in the opposite hands.
3. The handle from the right pulley should be in your left hand, and the handle from the left pulley should be in your right hand. The cables should be crossed and pulled tightly.
4. Keep your arms perpendicular to your torso and your elbows slightly bent; exhale as you pull your arms open and out to the sides.
5. Hold for a count of two. Inhale as you slowly return to the starting position. Repeat for desired reps.

7. One-Arm Rear Delt Cable Fly

You can do this exercise using one arm at a time, allowing you to alter the range of motion by adjusting the start or finish position.

This unilateral version makes it possible to raise your hand higher and get a longer stretch at the bottom, thereby generating more work for the posterior deltoid. Stabilize your torso by resting your free hand on your thigh.

How To Do

1. Lean forward at the hips, place your right hand on your thigh and hold a dumbbell in your left hand with your arm extended straight down.
2. Raise the weight straight to the side until your arm is parallel with the floor.
3. Pause momentarily at the top of the motion before slowly lowering the weight back down to the starting position.
4. Repeat with the right arm.

8. Standing Cable Rear Delt Fly

When you’re standing, your core muscles have to work overtime to keep you balanced and upright. This means you’re not just working your shoulders, but also strengthening your abs and lower back at the same time. It’s like a two-for-one deal.

The standing position allows for a greater range of motion compared to seated or machine variations. This means your rear delts are working harder.

How To Do

1. Adjust the cables to shoulder height and select a comfortable weight.
2. Hold a handle in each hand, palms facing each other.
3. Stand in the middle of a cable machine and bend your knees.
4. Pull the handles apart, moving your arms out to your sides in a wide arc. Hold the position for a brief second.
5. Slowly return the handles to their starting position.

9. Lying Reverse Dumbbell fly

Lying Dumbbell Reverse Fly is a strength exercise that works your traps and deltoids. If the traditional dumbbell rear delt fly causes strain on your lower back, try using an incline bench.

Instead of relying on your core to stabilize your body, you can rest your weight on the bench, which will help to better isolate your rear deltoids.

Lying rear delt fly is a great basic move. When done correctly, it can effectively target your neck, shoulders, upper back and upper body.

How To Do

1. Place two dumbbells on the floor, one on each side of a flat bench.
2. Lie prone (on your front) on the bench and grasp a dumbbell in each hand.
3. Spread your legs on the floor for support.
4. Keeping your elbows slightly bent, raise both arms out to the sides until the dumbbells are level with the height of your shoulders.
5. Hold for a count of two and then slowly lower the dumbbells to the starting position in a controlled manner.
6. Repeat for the prescribed number of repetitions.

10. Head-Supported Rear Delt Dumbbell Fly

The head-supported rear delt dumbbell fly is also known as the head-supported bent-over dumbbell reverse fly.

Keep your torso horizontal to target your posterior deltoids during the head-supported reverse dumbbell fly.

The more upright your torso is, the more emphasis you will place on your lateral deltoids instead of on your posterior deltoids.

How To Do

1. Raise a bench to hip height and hold a dumbbell in each hand, bend at the hips, and rest your forehead on the edge of the bench.
2. Your back should be straight, your arms should hang in front of you, and your palms should face inward (neutral grip).
3. Keeping your elbows slightly bent, raise both arms out to the sides until the dumbbells are level with the height of your shoulders.
4. Hold for a count of two, and then slowly lower the dumbbells to the starting position in a controlled manner.
5. Repeat for the desired number of repetitions.

Rear Delt Fly Workout Routines

The rear delt flys can be incorporated into your workout routine in various ways. Here are some options:

1. As a standalone exercise: Do on 3–4 sets of 8–12 reps.
2. As part of a shoulder workout: Do them along with other shoulder exercises.
3. As part of a full-body workout: Do them with other compound exercises like squats, deadlifts, and bench presses.

1. Shoulder-Focused Workout Routine

2. Upper Body Strength and Definition Routine

3. Full-Body Strength and Stability Routine

4. Push-Pull Split Routine (Pull Day)

FAQs

How Should I Integrate Rear Delt Fly Into The Rest Of My Workout?

The easiest way to incorporate the rear delt fly is with other shoulder exercises.s.

Because it is an isolation exercise, beginners should probably perform it after any compound shoulder movements (such as shoulder press, etc.) have been completed.

This enables the already fatigued rear deltoids to be driven into an even deeper state of exhaustion by the (relatively) fresh triceps and anterior/lateral deltoids.

What equipment do I need to perform the rear delt fly exercise?

The rear delt fly can be performed with various equipment, including dumbbells, resistance bands, and cable machines.

Choose the equipment that is most comfortable and accessible for you.

Can I perform the rear delt fly exercise at home without equipment?

Yes, you can perform a modified version of the rear delt fly exercise at home without equipment. Use water bottles instead of dumbbells.

Takeaways

Now that you know a few variations for your rear delts fly, hit the gym and try each one to get the full effect. Don’t limit yourself to variations on this exercise, either.

Seek out new and interesting ways to perform all your staple movements so that you never get stuck waiting at the gym, never grow bored, and always keep growing.

References

• Schoenfeld B, Sonmez RG, Kolber MJ, Contreras B, Harris R, Ozen S. Effect of hand position on EMG activity of the posterior shoulder musculature during a horizontal abduction exercise. J Strength Cond Res. 2013 Oct;27(10):2644-9.
• Lars L Andersen, Michael Kjær, Christoffer H Andersen, Peter B Hansen, Mette K Zebis, Klaus Hansen, Gisela Sjøgaard, Muscle Activation During Selected Strength Exercises, Physical Therapy, Volume 88, Issue 6, 1 June 2008

Manish Kumar

Manish is a NASM-certified fitness and nutrition coach with over 10 years of experience in weight lifting and fat loss fitness coaching. He specializes in gym-based training and has a lot of knowledge about exercise, lifting technique, biomechanics, and more.

Through “Fit Life Regime,” he generously shares the insights he’s gained over a decade in the field. His goal is to equip others with the knowledge to start their own fitness journey.