Muscular balance is important for developing a well-rounded physique and healthy movement for training, regardless of whether it is for strength or muscle mass. The rear delts are important muscle groups to have sufficient muscle mass on.
So what are underdeveloped rear delts and how do you fix them? Underdeveloped rear delts are when the muscles back of the shoulders do not have enough mass or strength. You can fix this by doing isolation and compound pulling exercises to target the rear delts, increasing your rear delt training frequency and volume, using proper technique, and lifting with a full range of motion.
As well, you can incorporate pauses and tempo training when performing rear delt exercises and move your rear delt exercises to the beginning of your workout.
In this article, I will discuss what rear delts are, what it means for them to be underdeveloped, why they can become underdeveloped, and what the implications are of having underdeveloped rear delts. I will also go through a series of solutions for targeting them.
Table of Contents
What Are the Rear Delts?
The rear delts refer to a portion of the muscle fibers that make up the deltoids. They are located on the posterior side of the deltoid, which means they are behind you. They attach from the shoulder blades, or the scapula, to the upper arm bone, which is called the humerus.
They have the following actions:
- Shoulder extension – bringing the arms from in front of you down toward the back of you behind your hips.
- Shoulder horizontal abduction – bringing the arms from in front of you outward horizontally towards the back of you behind your shoulders.
- Shoulder external rotation – turning your elbow crooks outward so they face out towards the side of you.
What Does It Mean to Have Underdeveloped Rear Delts?
If you have “underdeveloped rear delts,” it means that these muscles in the back of your shoulders are smaller or weaker than they could be or should be relative to the rest of your upper body.
They can be underdeveloped in terms of strength or muscle mass, although strength and muscle mass have a strong correlation with each other. If you increase muscle mass in the rear delts, the chances are that you will increase strength there.
They are referred to as underdeveloped relative to either the task they need to do or other muscle groups. So either the rear delts are not big and strong enough to perform something, or they are imbalanced relative to other muscle groups – namely, the front delts (the front part of your shoulder), chest muscles, or back muscles.
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Reasons Why You Have Underdeveloped Rear Delts
Here are 2 reasons why you may have underdeveloped rear delts:
- Inefficient pulling or rowing exercise technique
- Not enough pulling exercises vs. pushing exercises
1. Inefficient Pulling or Rowing Exercise Technique
Just because you do enough pulling and rowing exercises for your posterior muscles (i.e., the muscles at the back of your body) does not mean your technique is correct and efficient enough to maximize growth in your rear delt muscles.
One factor may be that you are not maximizing the range of motion in your execution. When you maximize the range of motion, you can increase the stimulus for growth in the muscles you train.
Another factor may be the way you cue the movement of the pulling or rowing exercise. For example, in a horizontal rowing exercise, you may find that cueing your elbows to row outward and away from the midline may target the rear delts more and the lats less.
2. Not Enough Pulling Exercises vs. Pushing Exercises
Your training program may have too many pushing exercises when compared to pulling exercises. Over time, your body will adapt to the training that you give it, which may result in an underdeveloped posterior chain, including underdeveloped rear delt muscles.
Your rear delts are activated to different amounts in pulling exercises, so they are not short of being trained if you have a good balance between pulling and pushing exercises.
One way you can ensure you’re doing an uneven amount of pulling and pushing exercises is following a push/pull/lower split. It will allow you to train your push and pull muscles each twice per week.
What Happens If You Have Weak Rear Delts?
Many things can happen or correlate with having weak or underdeveloped rear delts:
- Poor posture
- Increased chance of upper body injuries
- Asymmetries in physique
- Discomfort performing low bar squats
1. Poor Posture
Having underdeveloped rear delts may correlate to having poor posture. Poor posture may refer to having an overly rounded forward posture.
Not having well-developed rear delts may not necessarily cause poor posture, but it may be a symptom of not having enough pulling exercises as opposed to pushing exercises.
This is particularly relevant to more beginner exercisers or lifters. Beginners often have a poorly developed posterior chain (which are the muscles behind you) and often over train pushing muscles (the chest, triceps, and shoulders) versus pulling muscles (the back and biceps).
Increased Chance of Upper Body Injuries
Rear delts help stabilize the shoulder joint and assist the shoulder movement during pulling movements. If you do not have strong enough rear delts, you may risk losing stability in the shoulder during exercises such as the bench press, which can cause injuries to the shoulders or other upper body muscles.
For the bench press in particular, you may find that your shoulder blades do not stay stable when they are on the bench as you execute the movement. Strong rear delts help protect the shoulder by stabilizing it and keeping it in position as you press. They also create padding between your shoulder blades and the bench.
Learn more about how the rear delts work in the bench press in our guide to the muscles used in the bench press.
Asymmetries in Physique
Having an underdeveloped pair of rear delts relative to your front deltoids can make your physique look asymmetrical. It can also cause you to look naturally more hunched forward than you actually are.
Discomfort When Performing Low Bar Back Squats
One of the defining factors of how to position a barbell in a low bar back squat is its placement specifically on top of the rear delts.
When you pinch your shoulder blades back and down, the rear delts flex and create a shelf for the barbell as you squat. If you have underdeveloped rear delts, the barbell may press into your shoulder blades, which makes it very uncomfortable. The barbell may also slide down your back as you perform the low bar back squat.
This is undesirable because you lose stability and balance of where the barbell is relative to your center of mass. Also, you risk straining your shoulders as the barbell forces its way down your back.
8 Ways to Fix Underdeveloped Rear Delts
To fix your underdeveloped rear delts, here are 8 solutions:
- Increase the training sets per session
- Increase the training frequency per week
- Increase pulling exercises in training
- Change your exercise selection
- Adjust your exercise technique and cueing
- Maximize range of motion
- Increase tempo and add pauses
- Rearrange exercise order in your workout
1. Increase the Training Sets Per Session
The simplest strategy that you can monitor and implement is to increase the training sets of the exercises that target your rear delts.
This may include increasing sets for all of the isolation and compound pulling exercises in your program (check out face pulls, for example). Isolation exercises are exercises that only train the rear delts. Compound exercises are exercises that recruit other muscle groups in addition to the rear delts.
Increasing the number of training sets may be as low as having 1 more training set across the rear delt exercises of your program. It is better to be conservative with increasing sets so as not to increase risk of injury from overtraining.
2. Increase the Training Frequency Per Week
Another way to fix underdeveloped rear delts is to increase the training frequency per week of training the rear delts to at least twice per week.
The current body of research has shown that training muscle groups twice a week is the sweet spot for building muscle mass.
If you’re not sure how to structure a high-frequency training plan, check out our guides on creating a 5-day powerlifting split and a 6-day powerlifting split.
3. Increase Pulling Exercises in Training
You can also increase the number of pulling exercises that target the rear delts in your training. For example, if you are doing 2 pulling exercises per week, you should try increasing it to 3 or 4 pulling exercises in total.
It may also be useful to select exercises that move very differently from the ones you are already doing.
For example, if you are doing a lot of vertical pulling in your training (such as pull-ups or lat pulldowns), it may be wise to select more horizontal pulling (such as barbell rows). If you are doing a lot of wide grip pulling, you may want to choose more narrow grip work.
This will increase the different ways your rear delts are activated.
4. Change Your Exercise Selection
Research has shown that strategically varying the exercise selection over time can have a beneficial effect on muscle mass in certain regions. This does not mean changing the exercises on a weekly basis but changing the exercises after certain periods of consistent training.
This research also showed that the reverse pec deck, or machine rear delt fly, is superior to seated rows or lat pulldowns in terms of rear delt activation. So if you do not have this exercise in your training, it may be useful to have it now. You may even want to use this exercise as a pre-exhaust for your rear delts.
Pre-exhausting a muscle group refers to isolating a muscle group with an exercise before supersetting it with another exercise (normally a multi-joint or compound exercise) immediately afterwards. So the muscle in focus gets fatigued before training it with a bigger compound exercise.
Check out my favorite rear delt exercises for ideas on which movements you can add to your training program.
5. Adjust Your Exercise Technique and Cueing
You can also adjust the way you execute certain exercises or change the way you cue yourself during execution. This may change the emphasis on the muscle groups you are training.
For example, for a seated cable row, you may adjust your elbow angle so that it flares out more to move the focus away from the lats and more into your upper back and rear delts. If the cable handle allows it, you may also change your cueing so that you are pulling your elbows “outward” as opposed to “backward” and not targeting your trapezius muscle as much.
Another example is the lateral raise. This research showed that just by internally rotating your arms (i.e., turning your thumbs to point downward and elbows to point upward), you can target your rear delts more.
6. Maximize Range of Motion
Maximizing the range of motion is a rule that anyone who wants to increase hypertrophy should follow.
If you are not using full range of motion, now may be the time to implement this as this may be key to developing your rear delts more in your pulling exercises.
7. Increase Tempo and Add Pauses
You may also want to experiment with increasing the tempo and/or adding pauses into your repetitions when training. By adding a slower tempo or adding a pause, you increase the time under tension on the muscles, which may have a beneficial effect on the stimulus for muscle mass on the rear delts.
For example, if you are performing a reverse pec deck, you can follow a count of 3 or 5 seconds when returning the machine handle back to the starting position.
8. Rearrange Exercise Order in Your Workout
Research shows that exercise order does not matter so much when training for muscle hypertrophy but does matter when training for muscular strength.
If your rear delts are weak, you may want to keep the rear delt exercises at the start of the workout rather than the middle or end. This is when you are freshest and can lift more weight.
8 Best Exercises For Underdeveloped Rear Delts
Here are the 8 best exercises for fixing underdeveloped rear delts:
- Machine Rear Delt Fly
- Wide Grip Cable Row
- Close Grip Lat Pulldown
- Cable Rear Delt Pull Apart
- Cable Rear Delt Fly
- Chest-Supported Rear Delt Fly
- Lumbar Lat Pull Around
- Single-Arm Chest-Supported Pulldown
1. Machine Rear Delt Fly
The machine rear delt fly is also known as the reverse pec deck. This is probably the most well-known rear delt machine isolation exercise that is performed in most gyms around the world.
This exercise also activates the trapezius and rhomboid muscles.
How To Do It
- First, adjust the seat so that the handles of the machine are roughly at shoulder or just under shoulder height.
- Select the desired amount of weight on the machine stack.
- Sit down with the front of your torso facing into the machine and hold onto the horizontal handles with an overhand grip.
- Take a deep breath in and exhale as you swing the arms out until your arms are level with your shoulders.
- Inhale as you slowly return the handles back toward the starting position.
- Repeat for the desired number of repetitions.
How To Program It
The machine rear delt fly or reverse pec deck can be performed close to failure and with high repetitions. Here is how I recommend programming it:
- 2 to 4 sets
- 12 to 15 repetitions
- 2 or less reps in reserve
Pro Tip
To keep the focus on the rear delts, think about reaching outward and away from your midline when you swing your arms out. This helps keep the tension more on the rear delts rather than the upper traps and rhomboids, which are responsible for pinching your shoulder blades. If you think about swinging backward, you’ll feel more on your traps and rhomboids.
2. Wide-Grip Cable Row
The wide-grip cable row is a popular upper back exercise you can perform on an adjustable cable machine or dedicated seated cable row machine. You will need to use a long bar handle or lat pulldown handle for this exercise.
The other muscle groups that the wide-grip cable row activates are the biceps, trapezius, and rhomboids.
How To Do It
- Attach the long bar handle or lat pulldown handle onto the end of the cable.
- Sit on the seat or, if you are using an adjustable cable machine, a makeshift seat with a bench or exercise step.
- If you are using an adjustable cable machine, ensure that it is about chest level.
- Hold onto the handle with a wide overhand grip, and keep your torso upright.
- Take a deep breath in and exhale as you row the bar handle towards your lower chest level. Ensure that you keep your elbows flared out.
- Return the handle back to the start and stop when your arms fully extend. Make sure you maintain your upright torso angle.
- Repeat for the desired number of repetitions.
How To Program It
As the wide grip cable row is more of a compound exercise, you should try to use more medium reps and keep a moderate number of repetitions left in reserve. Here is a suggestion on how to program it:
- 3 to 4 sets
- 8 to 12 reps
- 2 to 4 reps in reserve
Pro Tip
To keep the priority on the rear delts, keep your shoulder blades pinched throughout the repetitions. Most people may think that this will work the traps and rhomboids more, but this ensures that the traps and rhomboids do not stretch and contract as much so that your rear delts can do that more.
3. Close-Grip Lat Pulldown
The close-grip lat pulldown is a good lat pulldown variation to target the rear delts. This is because your shoulder goes through a much longer range of motion through the rear delts than the wide grip lat pulldown. When you allow your arms to move up towards the side of your ear, you maximally stretch your rear delts.
How To Do It
- Attach a V grip handle onto the lat pulldown. If you do not have one, a regular lat pulldown is sufficient.
- If you do use a regular lat pulldown handle, grab onto the handle with a shoulder-width and underhand grip.
- Sit down and position your thighs underneath the thigh pad while holding onto the chosen pulldown handle.
- Make sure your arms are relaxed, your abs are engaged, and your back is flat.
- Exhale as you pull the handle down and cue bringing your elbows down towards the back of your pelvis.
- Inhale as you slowly return the pulldown handle back to the top.
- Repeat for the desired number of repetitions.
How To Program It
The close-grip lat pulldown is a compound exercise where it is easy to lose posture, so you should not go too heavy on it. Here is a suggestion on how to program it:
- 3 to 4 sets
- 8 to 12 reps
- 3 to 5 reps in reserve
Pro Tip
Most people will use a fast speed when pulling down but slow speed when returning the lat pulldown bar back up. The problem with this is that when the weight gets hard and you start to fatigue, it is very easy to unconsciously swing your torso to get the weight down.
For the close-grip lat pulldown, aim to pull the lat pulldown handle down with a slower tempo of about 2-3 seconds and use the same tempo on the way up.
4. Cable Rear Delt Pull Apart
The cable rear delt pull apart is a useful cable exercise to target the rear delts. You will need to use an adjustable cable column or a lat pulldown machine with a pair of single-hand cable handles.
How To Do It
- Set a cable to stem from about shoulder height and attach a pair of single-hand cable handles in the carabiner.
- Hold onto the cable handles and stand far away enough that your arms are taut as the cable stack is just about lifted off from the bottom.
- Pull the cable handles towards your collarbone while pulling your elbows outward away from your torso.
- Stop when your elbows are directly by the side of your shoulders and slowly return the cable handle back until your arms are straight.
- Repeat for the desired number of repetitions.
How To Program It
The cable rear delt pull apart requires balancing your body when you execute your repetitions. You do not want to train towards failure or go heavy on it, as you may lose balance. For this reason, you should aim for higher reps but not go too close to failure.
Here is a suggestion on how to program it:
- 2 to 3 sets
- 12 to 20 reps
- 4 to 5 reps in reserve
Pro Tip
To avoid allowing your traps to take over in this exercise, it is important that you cue yourself to think about pulling the cable handles outward and apart as if you were opening a bag of chips. This will keep the tension more on the rear delts than on the traps.
Thinking about pulling backward encourages more pinching back of the shoulder blades, which activates the traps plenty.
5. Cable Rear Delt Fly
The cable rear delt fly is a great isolation exercise for the rear delts. You will need to use a dual adjustable cable pulley machine. Cable handles are optional as you can just hold onto the ends of the cable.
How To Do It
- Set the cable ends to start around shoulder-height level.
- Stand between the cable columns and grab each end of the cable with an overhand grip with opposite hands, i.e., the right hand holds onto the left cable and vice versa.
- Hold the cable ends directly in front of you with your arms parallel to the floor.
- Pull against the cable ends until your arms are directly by the side of your shoulders.
- Ensure that your elbows stay straight and fixed throughout the execution.
- Return the cable ends towards the front of you again.
- Repeat for the desired number of repetitions.
How To Program It
When doing the cable rear delt fly, it is very easy to lose posture and stability in your whole body and start using momentum to finish off repetitions. For this reason, it is best to stay clear away from failure.
Here is what I suggest for programming this exercise:
- 2 to 3 sets
- 10 to 15 reps
- 3 to 5 reps in reserve
Pro Tip
When performing the cable rear delt fly, try to cue yourself to stretch your arm span as wide as possible as opposed to thinking about bringing your arms as far back as possible. This will minimize activation on the traps and maximize effort from the rear delts.
That said, you will not be able to eliminate tension on the traps, so you should still expect some tension there.
6. Chest-Supported Rear Delt Fly
The chest-supported rear delt fly is an effective dumbbell exercise to activate the rear delts. You will also need to use an incline free-weight bench.
How To Do It
- You need to first set up the incline of the free-weight bench to a level that is as low as possible but high enough that your arms or dumbbells do not touch the ground or base of the bench while holding onto them.
- Lie down on top of the bench with your chest on the pad but head above the end of the bench.
- Hold onto a pair of dumbbells with your palms facing away from you, and make sure your thumbs face each other.
- Take a deep breath in and exhale as you elevate your arms until they are parallel to the floor.
- Make sure you keep a soft bend but fixed angle in your elbows as you do this.
- Slowly turn your arms back down to the dead hang position and inhale.
- Repeat for the desired number of repetitions.
How To Program It
The chest-supported rear delt fly is an exercise you can train quite close to failure without worrying about losing balance. Here is a suggested starting point for programming:
- 2 to 3 sets
- 10 to 15 reps
- 1 to 3 reps in reserve
Pro Tip
When performing this exercise, try to keep your shoulder blades pinched back throughout the repetition so the majority of the movement happens at the rear delts more than at the upper and lower traps. If you allow your shoulder blades to freely move, your traps end up doing a lot more work than the rear delts.
7. Lumbar Lat Pull Around
The lumbar lat pull around is a less common cable exercise that was initially intended to target the lats and the biceps. However, it is very effective at activating the rear delts because of the direction in which you pull the cable.
How To Do It
- Set up a cable machine to start from about head level and attach a single arm handle.
- Stand to the side facing perpendicular to the cable column and grab the cable column with your nearest arm.
- Reach across to hold onto the cable handle with your furthest arm and keep your torso facing perpendicular to the cable column.
- Face the column and row the cable across your body as if you were drawing a bow and arrow.
- Slowly return the cable until you can get your arm across as much as possible without rotating your torso.
- Repeat for the desired number of repetitions.
How To Program It
You can brace yourself quite effectively with this exercise, so you can potentially push to closer to failure with a moderate repetition range. You do not want to do fewer reps with very heavy weight, as you may risk losing posture.
Here is a suggested starting point for programming:
- 2 to 3 sets
- 8 to 12 reps
- 2 to 3 reps in reserve
Pro Tip
A good cue for this exercise is to think about bringing the elbows as far away from the body as possible to optimize how much rear delt activation you get. If you want to activate the lats the most, think about bringing your elbows closer to the top of the pelvis.
8. Single-Arm Chest-Supported Pulldown
The single-arm chest-supported pulldown is a great cable exercise to help stabilize the torso when targeting the rear delts. You’ll need to use a cable machine and an incline free-weight bench.
How To Do It
- Set up a free-weight bench to be as upright as possible about 2 to 3 feet in front of a cable column.
- Attach a single-arm handle to the cable column and set it up so that your arms are roughly at 45 degrees.
- Sit on the seat while bracing yourself into the bench pad and reach over to grab the cable handle.
- With an overhand grip, row the cable back and downward.
- Slowly return the cable handle back until your arms fully extend.
- Repeat for the desired number of repetitions, then repeat the same process for the other arm.
How To Program It
As you can isolate your body well with this exercise, you can train it towards failure and benefit from a variety of rep ranges.
Here is a suggested starting point for programming:
- 2 to 4 sets
- 8 to 15 reps
- 1 to 3 reps in reserve
Pro Tip
To minimize activation on the biceps and maximize activation on the rear delts, think about leading with the elbows and bringing them as far back as possible. By thinking too much about leading with your hands, you may concentrate on flexing through your elbows more, which prioritizes the biceps.
Other Guides for Fixing Underdeveloped Muscles
About The Author: Norman Cheung ASCC, British Powerlifting Team Coach
Norman Cheung is a powerlifting and accredited strength and conditioning coach under the UKSCA. He has been coaching powerlifting since 2012 and has been an IPF Team GB coach since 2016. He has experience coaching various lifters, from novices to international medallists and international university teams. Alongside coaching, he takes an interest in helping powerlifters take their first step into coaching. He currently runs his coaching services at strongambitionscoaching.com.
