Written by Garett Reid | NSCA, CSCS, CISSN, M.S.E.S.S
Fact checked by Kirsten Yovino, CPT Brookbush Institute
FACT CHECKED
The cable rear delt fly is perhaps the best isolation exercise for your posterior deltoid and back. You need to be doing them. A powerful back with rear delts that pop is one of the most impressive features on a lifter; perhaps the most impressive depending on who you ask. And for a good reason too. A large thick back with definition looks extremely impressive and paints a picture of dominance. While the chest has two pecs, the back is covered in various muscles making their prominence stand out that much more.
The most common back exercises are deadlifts, back rows, and pull-ups and there’s nothing wrong with that. These are all fantastic exercises that allow you to move some heavyweights and generate some ultimate strength and growth. However, to really get your muscles to pop, you need to start doing the cable rear delt fly mentioned above.
The cable rear delt fly is an isolation movement that allows you to really hone in on the muscles that need it. To get the most out of what this exercise offers, you need to understand what it actually does as well as its proper form. Plus, there are quite a few variations that you’re probably not aware of. In this article, you’re going to learn:
- What is the cable rear delt fly?
- What muscles does the cable rear delt fly train.
- How to properly perform the cable rear delt fly.
- Benefits of the cable rear delt fly.
- Multiple cable rear delt fly variations.
What Is The Cable Rear Delt Fly?
The cable rear delt fly is an isolation movement that trains the posterior muscles. This may seem confusing since an isolation movement “isolates” a muscle, doesn’t it? Most of the confusion comes down to terminology, so a better term to use may be “single-joint exercise”.
The joint at which the cable rear delt fly movement occurs is the shoulder. This happens as the arms are brought back while being spread out like a big hug. Have you seen a cable chest fly? Same exact thing, only opposite; you pull backward rather than forward.
There are multiple hand attachments and variations that can be used during this movement.. However, the general motion will have a trainee set up a pulley and grab the handle attachment by crossing the arms across the body. Left arem grabs the right handle and vice-versa while the pulley are set at about head level.. While keeping a slight bend in the elbow, the trainee will pull the arm back as if they’re getting ready to give someone (I hope they know them) a huge hug.
More detailed instructions will be given below, but this is to give you a general idea of the movement. Knowing this will make understanding what muscles are trained easier as well as in what manner. From a biomechanical perspective, this motion is known as horizontal shoulder abduction. Therefore, every muscle involved in horizontal abduction is going to get a workout.
What Muscles Does The Cable Rear Delt Fly Train?
The rear delts obviously play a massive role performing the rear delt fly (the movement is named after them, so I’d hope so!). That being said, as briefly stated a few times, while often called an “isolation” movement, the cable rear delt fly trains a lot more muscles than just the deltoids. In fact, there are quite a few muscles that play a significant role and not just as “stabilizers”. Here are the muscles used during the cable rear delt fly.
Rear Deltoids (Posterior Deltoids)
As the name of the exercise implies, the rear deltoid is a significant mover in this exercise. The shoulder muscle (deltoids) is composed of 3 heads. These heads are needed as the shoulder joint is what’s known as a “ball-and-socket” joint. These are the most mobile joints, so these 3 heads must manipulate the arm in various directions.
The rear deltoid sits on the posterior of the body and is responsible for what would be known as “pulling” movements and often works synergistically with other back muscles. One of the main movements it’s responsible for is shoulder horizontal abduction, as seen during the rear fly.
Trapezius (Traps)
The trapezius, aka “traps,” are a dominating set of muscles that sit on the middle of the back. There are 3 “sections” that make up the traps.
- Upper Traps- This part of the muscle runs on the top of the very upper back, almost shoulder to shoulder. It also runs up the neck to the base of your skull
- Middle Traps- This section is about as wide as your entire shoulder joint and runs from the spine to the scapula
- Lower Traps- This is the largest portion. It runs down from the middle traps and begins to taper off as it runs down the back. It eventually ends around mid-way down the back.
Every portion has a slightly different role, but their primary function is scapular retraction and control. This is crucial as almost every posterior motion, including the rear delt fly, requires scapular retraction for optimal effect AND mitigation of injury. Therefore, it works synergistically to aid in shoulder abduction.
Infraspinatus & Supraspinatus
The infraspinatus and supraspinatus are two small muscles that makeup half of the rotator cuff muscles. While small, they play an essential role in strengthening the shoulder capsule and assisting in the abduction of the arm. These two small muscles also provide support for the scapula, rotator cuff, and shoulder.
Rhomboids
The rhomboids are actually divided into major rhomboids and minor rhomboids. If you were wondering why this muscle is called “rhomboids”, it’s because the minor rhomboid sits superior (above) the major rhomboid and together form a rhomboid-shaped muscle. They sit beneath the trapezius muscle and connect the scapula to the spine. They function in a very similar manner as the traps to retract the scapula and provide scapula stability.
Teres Major and Minor
Both the teres major and teres minor run from the humerus to the scapula. While tiny, they play an essential role in pulling the arm back and providing stability. Also, these muscles help guide the action of the posterior deltoid by preventing the humeral head from sliding upward as the arm is abducted. It also works synergistically with the posterior deltoid during abduction.
Triceps
You don’t usually think about the triceps when talking about pulling movements. However, the triceps play a vital role. During the exercise, the arms must be extended and held as they are drawn back. As the hands must have resistance, the elbow will want to flex to relieve the stress. You obviously don’t want that to happen so the triceps must fire to hold an isometric contraction. If you have weak triceps, you’ll find out real quick-performing rear delt flies.
Forearm Extensors
The forearm extensors work in the same manner as the triceps, except their job is to keep a solid wrist.
How To Properly Perform The Cable Rear Delt Fly
The set-up for the cable rear delt fly is pretty straightforward. The hardest part is getting a dual cable machine with both sides open. As gyms can be busy, this can sometimes be a problem. If you experience this, we list the perfect variation below to continue your workout.
The first thing you’re going to want to do is set the cables up at about head level. This movement tends to work a bit better when pulling at a slight angle. Also, find a set of handles and attach those as well (Below has other variations). Once those are set up, you’re ready to get into position.
To get the correct body placement, pretend that a line exists on the ground that connects both pulleys. The first thing you’re going to want to do is to put yourself in the exact middle. You don’t need to bust out a ruler but be sure you’re not obviously biased to one side. If you are off-balanced, you should feel it when you grab the handles. Once you’re in the middle, you’ll then want to stand a couple feet behind the emergency line. When you’re looking forward, the pulley should be slightly in front of you so that when you stick your arms out, they are still slightly behind the line. That is because you want the pull to be smooth. If your hands start behind that line but then go in front when you come out front, the cable will jump and not be smooth.
Now grab the handles with a neutral grip and let the weight pull your arms as the movement starts with your arms fully crossed. Be sure to keep a slight bend at your elbow. Before you pull, you’re going to retract your scapula and keep them there.
When you begin the pulling phase of the movement, your arms will “sweep” across your body and end up on the other side. Before you pull, plan on what arm will go on top and which will go under when your arms cross in front of you. You can also alternate patterns for each rep. However you perform the movement, you want to pull back as far as you can, ideally with some slight hyperextension if possible. An excellent way to think about this movement is to pretend like you’re trying to touch your hands behind your back. Obviously, this won’t happen in this manner, but it’s an excellent thought to get the squeeze you’re looking for.
Regardless, give a good squeeze and then return in a slow and controlled manner.
Very Important!!! Your arms will stay in the same position for the entire movement. Extended with only a slight bend in the elbow. You will use an isometric hold in your arms to maintain this AS WELL as your wrists. As you pull, the resistance will want to flex your wrist. Don’t let it!!! This is going to require an isometric contraction from your forearm extensors that we discussed above.
Benefits of Cable Rear Delt Flys
Sure, training the cable rear delt fly is the most fun you’ll ever have (Sarcasm? You tell me…), but there’s a lot of other excellent reasons why you need to be doing it. Here are the top benefits to performing the cable rear delt fly.
Trains The Posterior Delt
Training shoulders is a must. Having well-developed delts can drastically improve your aesthetics. However, what most people seem to forget is that three heads of the shoulder have drastically different functions. When most people train shoulders, they perform movements like shoulder press, later raises, and upright rows. Nothing wrong with those at all as they are fantastic shoulder exercises, and you need to be doing them.
However, most of your shoulder exercises only train two heads, the anterior delt (front) and lateral head (side). What’s missing from shoulder exercises is the posterior delt or rear delt. To be fair, the posterior delt gets a lot of training with basically every pulling exercise. However, when it comes to isolating the muscle, it is often skipped over. Including the cable rear delt fly is going to make sure you train this head of the deltoid. Plus, it may just rattle your brain and make you remember you have posterior delt.
Improves Posture
Unfortunately, a lot of people’s posture needs some improvement. One of the best ways to do this is to include many posterior pulling exercises. While you get a lot of the heavy work in with rows, using an exercise that allows a lot of volumes is an excellent method to offset the amount of work in front of the body, both movements and daily life, such as writing or typing.
If you have poor posture, include a lot of cable rear delt flyes in your program. One method is to use this exercise as a mobility exercise or warm-up rather than a “strength” exercise. By this, we mean you do it every session with very lightweight and a ton of reps.
Strengthens The Entire Shoulder Complex And Scapula Muscles
Along with training the rear delt above, you saw that the rear delt fly actually strengthens a wide variety of muscles, including the rotator cuff muscles, and strengthens the scapular muscles. This is extremely important as poor scapular control and weak rotator cuffs are common causes for injuries. As the saying goes, “Strong things don’t break” (Or, “Weak things break easier”).
You don’t want to break your shoulder, and rear delt flys make it stronger, so to do them.
How To Program The Cable Rear Delt Fly
So, where does this exercise fit into your programming? While it could fit on your shoulder day, it’s actually a pulling movement which means it falls more in line with your back movements. Many people hear “deltoid” and assume it’s a pushing movement but remember, the shoulder muscle (deltoids) actually consists of three heads. While the other two heads are “pushing” muscles, the rear delt is a pulling. Also, remember that this movement works out plenty of other back muscles. Therefore it should be programmed with either your pulling session or back session.
However, there is some nuance. If you have one specific “shoulder day” or even “shoulder and arms”, you could easily throw the rear delts in there. One thing to consider is that when comparing the number of muscles and exercises, your back has a lot more to take care of. Therefore, moving the rear delt to “shoulder day” could open up room for another back exercise.
That being said, the rear delt cable fly is almost exclusively performed as a movement for muscle hypertrophy. Therefore, you’re going to want to use a smaller load that allows at least 8 reps. Still, this movement is generally done at even higher reps of 12+. Also, use a shorter rest break of 1:00-1:30.
Further, it’s a great movement to use as a finisher and perform to exhaustion. Regardless, due to your poor biomechanical advantage during the movement, you’re going to use lightweight, so check your ego.
4 Cable Rear Delt Fly Variations
Above, we dissected the traditional variation of the cable rear delt fly. This fly version is what is usually seen and is an excellent back exercise in its own right. That being said, there are several variations that you can do to get some different muscle activation. While the primary function of the exercise is there, these fly variations can really feel like a new movement.
1. Supinated Grip (Overhand Grip) Cable Rear Delt Fly
One of the more common variations is to simply use a supinated or overhand grip. This is most often performed by not using a handle at and instead grabbing the cable directly. As the hand is rotated, it will also hit delts a bit differently as there will also be some rotation of the humerus. Keep in mind that most trainees actually feel a bit stronger using this variation so you could use more weight. You could even create a compound set by first using these, then dropping the load and using the neutral grip.
2. High Cable Rear Delt Fly & Low Cable Rear Delt Fly
Two significant variations can be done with a very simple adjustment; moving the cable pulley either high or low. Doing so will allow you to target a different set of muscles.
By placing the cable high, you will be pulling in more of a downward angle. To be clear, the set-up and form is exactly the same as the traditional variation. The difference is that your hands will begin at a higher level, generally slightly above your head, and then come down as they cross your body. You will then pull down with your hands, usually reaching waist level. It almost looks as if you’re drawing an “X’ with your hands.
What this will do is hit your lower back and lats to a higher degree. If you look at the movement, it looks a bit similar to pull ups.
The other variation simply has you lower the pulley system. Now, everything is the same except your hands will cross your body and start at a lower position, generally around the waist. Next, you pull your arms upwards. This is almost like doing a massive lateral shoulder raise. As you’re pulling up, you’re going to get more activation in your upper back. Further, you’re going to hit your medial deltoids as this is very similar to a lateral raise.
You can also use the different grip variations.
3. Unilateral Cable Rear Delt Fly
The unilateral rear fly simply has you use the hand. You can do this with any of the variations. Everything is exactly the same except you use one hand. Using a unilateral exercise can cause more activation in the stabalizer muscles as well as the core. This is because the core will work as an anti-rotation fashion as it will need to resist the body’s tendency to turn. Actually, this is a huge benefit as studies show anti-rotation training for the core is superior method of core training, especially when it comes to injury-prevention.
That being said, what makes this variation so important is that it’s not unusual to discover only one side of the pulley machine is open. Remember above we said we had a solution to that issue? Well, this is it. You can still get a great workout using one arm at a time.
The main difference would be to use shorter rests breaks between each arm when it comes to programming. Since one arm can rest as the other arm performs the movement, you don’t need to rest as long for each component.
4. Bent-Over Cable Rear Delt Fly
The bent-over cable rear delt fly is the first variation to have a unique set-up. This movement has you bending over and is usually performed with one hand.
To perform this variation, you will set the pulley at its lowest position. You will then stand looking across so that the cable will run in front of you. Next, bend over and grab the handle with the arm that’s away from the cable. Try to bend over as far as you can. In this position, you should be bent over with your far arm crossing your body. You can use any handle or grip you want for this.
Next, all you’re going to do is perform a reverse fly and pull your arm up in the same motion as the traditional cable fly.
Here are some other ways you can do cable rear delt flys with different body positions...
Incline Bench Cable Rear Delt Fly (Prone)
Incline Bench Cable Rear Delt Fly (Supine)
Supine Flat Bench Cable Rear Delt Fly
Cable Rear Delt Fly Alternatives
Want a break from rear delt flies? Here are some fantastic variations that will train the muscles with the same movement, albeit slightly different.
BAND PULL APARTS
Band pull aparts are not one of the best exercises to improve shoulder mobility and strengthen the posterior muscles. Plus, it’s extremely easy to perform. To do band pull aparts, you’ll first need a high-quality resistance band. Next, simply hold the band out in front of you with both hands so the band is at eye level. There should be a minimal amount of tension in the band from the begging. Next, you perform the same exact motion using horizontal shoulder abduction to bring your arms back and pull the band apart. Last, let the band come back to the starting position but don’t lose tension! Come back slow and controlled without with outgoing so far as to lose tension.
The one thing to remember is to keep your hands high for the entire movement.
DUMBBELL REAR DELT FLYES
Dumbbell rear flyes are almost exactly like the cable flyes. The difference comes in the set-up as you’ll use dumbbells. When using dumbbells, you will need to bend over so that your torso is nearly parallel with the ground, similar to the bent over cable rear delt fly. You then use a dumbbell to perform the rear delt fly. You can use any grip as well as perform the movement bilaterally or unilaterally.
Another option is to set up a bench on a slight incline. This is very effective as the bench supports your body and allows you to push into it for more force.
Related: 12 Rear Delt Dumbbell Exercises
FACE PULLS
Face pulls are a great exercise for your rear delts and you will use the cable machine for this one. It's also great for improving scapula stability and strength through activation of the traps, teres major, teres minor, and rhomboids.
Then, of course, you have the reverse pec deck machine that you can use for rear delt flys.
Bring Your Back Training To Another Level With Rear Flyes
Training the back is a favorite for a good portion of lifters. It lets you use heavyweight, and a big thick back screams power. All the heavy stuff is good, but for optimal back training, you need that variety. You need to chill out with the heavy loads and really concentrate on the burn.
The cable rear delt fly is the perfect exercise as it uses a light load and requires a tremendous mind-muscle connection. Further, it works the posterior muscles in a genuinely functional manner while allowing you to train multiple muscles with a single-joint exercise.
Cable rear delt flyes are a must for serious lifters.
Looking for another great fly variation? Check out how to do Standing Cable Flys.
Related Content:
Garett Reid
Author