All the best chest exercises involve both arms: the barbell bench press, the incline dumbbell press, the dumbbell flye, the cable flye, and even the humble — but underrated — push-up. On the other hand, single-arm (or leg) exercises are all the rage for building your back or legs.
Why, then, are single-arm chest exercises so often cast aside? Your pecs are a muscle like any other: They’re prone to imbalances and may require a more precise touch if you want them to grow.
If you’ve never done a single-arm chest flye before, you may have a deep reservoir of gains just waiting to be tapped. Here’s everything you need to know about the one-armed flye — and how to make insane gains with it.
- How to Do the Single-Arm Chest Flye
- Single-Arm Chest Flye Sets and Reps
- Common Single-Arm Chest Flye Mistakes
- Single-Arm Chest Flye Variations
- Single-Arm Chest Flye Alternatives
- Muscles Worked by the Single-Arm Chest Flye
- Benefits of the Single-Arm Chest Flye
- Who Should Do the Single-Arm Chest Flye
- Frequently Asked Questions
Editor’s Note: The content on BarBend is meant to be informative in nature, but it should not be taken as medical advice. When starting a new training regimen and/or diet, it is always a good idea to consult with a trusted medical professional. We are not a medical resource. The opinions and articles on this site are not intended for use as diagnosis, prevention, and/or treatment of health problems. They are not substitutes for consulting a qualified medical professional.
How to Do the Single-Arm Chest Flye
You can do the one-armed flye with just about any type of equipment, including dumbbells, a cable station, or on the pec deck machine. This guide will teach you how to perform the unilateral chest flye on a cable station, since it provides the most consistent tension to your pecs.
Step 1 — Set the Cables
There’s no specific height at which you must perform the single-arm flye. Wherever you usually set the pin for your standard flyes will work fine. If you aren’t sure, you can set up with the cable at, or slightly above, shoulder height.
From here, grab the handle with your working arm and take a slight step forward. The plates should pull off the stack and apply tension to your arm and chest. Use your free arm to grab ahold of a sturdy surface, or you can place your hand on your hip for stability.
Coach’s Tip: Turn your torso slightly away from the cable stack to further stretch your chest in the starting position.
Step 2 — Draw Your Arm Across
Once you’ve established your starting position, draw your working arm across your chest, squeezing your pecs the entire way. When performing the 1-arm chest flye, ensure that your working arm passes your midline to maximize mechanical tension on your pecs.
Coach’s Tip: Think about jamming your upper arm against your torso to fully contract your chest at the end of each rep.
Single-Arm Chest Flye Sets and Reps
As a single-arm, single-joint exercise, your options for programming this version of the flye are limited. However, that doesn’t mean they’re nonexistent. Here are two different ways you can utilize the single-arm chest flye to grow muscle or build on your endurance:
- For Muscle Growth: Try 2 or 3 sets of 12 to 15 reps with a moderate weight.
- For Muscular Endurance: Go for 3 sets of 20 reps with a light weight and a slow tempo.
Common Single-Arm Chest Flye Mistakes
When it comes to an isolation exercise like the single-arm chest flye, execution is everything. Getting this movement right comes down to how well you can nail the details while avoiding potential mistakes. Steer clear of these errors if you want to get the most value out of each set.
Twisting Your Torso
One of the biggest benefits of working your chest with one arm at a time is the added range of motion that comes from an exercise like the single-arm flye. However, you’re also very prone to twisting or tilting your torso since the resistance isn’t evenly distributed across your body.
This can negatively impact your mind-muscle connection, reduce your range of motion, or potentially increase your risk of injury. No matter what type of equipment you’re working with, fight to keep a stable torso the entire time. You can even try actively tilting your body away from the arm you’re working to keep yourself balanced.
Bending Your Elbow
The defining feature of any flye exercise is maintaining an extended (or nearly extended) elbow. Bending your arm too much when you perform a movement like the single-arm chest flye can shift the load away from your chest and onto your triceps or shoulders.
When you perform any manner of flye, ensure that your elbow remains nearly straight the entire time. You needn’t lock the joint out entirely — this may cause discomfort in your elbow — but the posture should be consistent from start to finish. If you find yourself tempted to bend your arm, you’re probably lifting too heavy.
Lifting Too Heavy
The barbell bench press and the single-arm cable chest flye lie on opposite ends of the pec-training spectrum. As you move from one to the other, the amount of weight you can work with drops significantly. You limit the amount of assisting musculature and increase your range of motion.
As such, don’t expect to push serious weight when you perform single-arm flyes. The movement is more about finding a good mind-muscle connection with the working side of your pecs and taking the tissue through a long, sweeping range of motion.
Single-Arm Chest Flye Variations
The single-arm chest flye is, essentially, a variation to begin with. As such, if you want to tweak the exercise, your best bet is to change the type of equipment you use. These are your three main options.
Dumbbell Single-Arm Chest Flye
Working with dumbbells for the single-arm chest flye probably isn’t ideal, but it’ll do the job in a pinch and bring some extra ancillary benefits along the way.
By laying on a bench and working one arm at a time with a dumbbell, you can emphasize the lengthened position of your pecs and get a great core workout in as well. Your abs and obliques will need to work overtime to keep your torso flush to the bench itself. Go for this version of the movement if you want to work more than just your pecs.
Cable Single-Arm Chest Flye
The cable tree is your best friend when it comes to flye exercises, whether you’re using one arm or two. This is due to the consistent resistance curve the cable provides; at the “top” of a free-weight flye, there’s almost no tension on your chest because the weight must obey gravity.
During a cable flye, your pecs must constantly resist the will of the cable as it attempts to pull your arm sideways, not push it downward. This means that, for the most part, the single-arm cable flye will be consistently challenging from start to finish.
Single-Arm Pec Deck
If you don’t want to use dumbbells and can’t find a free cable in your gym, the single-arm pec deck works just as well. In some cases, you may even find it preferable.
The arms of the pec deck station move independently along a fixed rail. This limits the customizability of the exercise as it applies to your body’s individual structure, but you make up for it with added stability. You can even use your non-working arm to brace your body against the rotational forces of working with one arm.
Single-Arm Chest Flye Alternatives
Few other movements accomplish as much as the single-arm chest flye. However, that doesn’t mean you can’t work your chest unilaterally with other exercises. You’ll just have to get a bit creative. Try some of these alternatives to the single-arm flye:
Single-Arm Floor Slider Flye
If you prefer to work with your own body weight at home, you can make great use of a standard floor slider as a chest-training tool.
The floor slider flye is far more difficult than it may appear. Not only do you apply most of your own body weight to one half of your pecs, you also have to stabilize yourself from head to toe. This movement is great for both building your pecs and developing rock-solid shoulder stability.
Single-Arm Dumbbell Bench Press
Single-arm presses work almost as well as flyes for targeted chest growth. You’ll just have to deal with a greater tendency to twist your torso, but the trade-off is higher mechanical tension on your pecs specifically.
The single-arm dumbbell bench press is also a great way to resolve any side-to-side discrepancies in strength, stability, or muscularity you may have.
Muscles Worked by the Single-Arm Chest Flye
The single-arm chest flye may be an effective isolator for your pecs, but that doesn’t mean there are no other muscles involved. To get the most value out of this movement, you need to know how your body responds to it.
Pecs
Your pecs are divided into two primary sections; the large, superficial pectoralis major and the deeper, smaller pectoralis minor. The pec major has two compartments as well; sternal and clavicular.
When you perform flyes from shoulder-height or higher, you primarily work the pec major through its full range of motion. One of the tissue’s primary functions is shoulder adduction; horizontal movement of your arm in space in towards your midline.
[Read More: The Best Ab Exercises & Workouts, According to a CPT]
Notably, your pecs can also draw your arm in further than just perpendicular to your torso. This is something you can exploit with single-arm flyes. When you work with both your arms simultaneously, they can’t cross each other comfortably.
Upper Back
Flyes may be an anterior, chest-focused exercise, but any movement at the shoulder joint will involve the musculature in your upper back to some degree.
Muscles like the rear deltoid, teres major and minor, or infraspinatus all attach to your shoulder blade. When you sweep your arm in space against resistance, these tissues provide support and control to your shoulder.
Certain single-arm flyes can be particularly potent for shoulder stability, particularly if you’re working with free weights like dumbbells or even a kettlebell.
Core
Any single-arm (or, especially, single-leg) exercise you perform will activate your core. During the single-arm chest flye, your external obliques and rectus abdominis contract isometrically — as in, without shortening or lengthening — to stabilize your trunk.
This doesn’t necessarily mean single-arm flyes are an ab exercise, but they will provide some mild stimulation to your abs. If you don’t often perform unilateral movements, this stimulus can actually be fairly potent.
Benefits of the Single-Arm Chest Flye
Targeted pec growth, side-to-side stability, and an unparalleled mind-muscle connection are just a few of the many benefits you can expect from the single-arm flye. Here’s a more detailed breakdown of what’s on offer:
Targeted Muscle Growth
When it comes to building muscle in your chest (or anywhere else, for that matter) you need the right tool for the job. Often, that tool is an exercise that you “connect” with — you can achieve this by taking auxiliary or assistive tissues out of the equation.
[Read More: The Best Bodyweight Exercises, + Workouts and Tips From a CPT]
The single-arm chest flye falls exclusively on your chest. Your triceps and deltoids are largely out of the picture. This lets you place every morsel of mechanical tension exactly where you want it for the best results possible.
Helps Address Imbalances
All unilateral exercises are “therapeutic” in nature. Specifically, allowing one limb to work while the other remains idle is a great way to identify, expose, and address any muscular deficiencies.
You can use the single-arm chest flye for isolated chest growth, sure. Along the way, you might just notice that one pec doesn’t contract quite as well as the other, or your non-dominant shoulder shakes a bit too much: All the more reason to keep the single-arm flye in your repertoire as a way of evening out these issues.
Who Should Do the Single-Arm Chest Flye
Wondering if the single-arm chest flye is right for you? If you fall into one of the following categories, it just might be. These two camps stand to benefit a great deal from some targeted chest training.
Bodybuilders
Bodybuilders rely on a wide, wide array of different exercises to facilitate muscle growth. These include staples like the bench press, back squat, pull-up, or overhead press, but if you’ve got muscle on your mind, you should incorporate plenty of small isolation moves as well.
The single-arm chest flye provides a stimulus that you really can’t get from other mainline chest exercises. It is, perhaps, the best way to stimulate your pecs while putting other muscles on the back burner.
If You Have a Muscle Imbalance
Single-arm flyes are great for hypertrophy, but you can also use them in a rehabilitative context. Balancing your body from left to right (or top to bottom) is crucial for more than building a symmetrical physique. You should strive to streamline your body’s performance as well. The single-arm flye is a great way to equalize your shoulder stability or pec strength.
Strong-Arm Your Gains
The right exercise can elevate your gains from the moment you pick it up. Big barbell presses are all the rage for chest growth (rightfully so), but you may be spinning your wheels with them. You may just need to switch things up and work with one arm instead.
The single-arm chest flye is convenient, easy to perform, and smashes your pecs in a way you simply can’t get from most other exercises. You have nothing to lose and pecs to gain, so get to it.
FAQs
Still wondering about the single-arm chest flye? These common questions and answers should put your mind at ease.
Is the single-arm chest flye bad for my shoulders?
Absolutely not! Single-arm movements are often more challenging for the musculature around your shoulder, but that isn’t the same thing as those movements being dangerous. As long as you work with reasonable loads and strive for good technique, you have nothing to fear.
When should I do single-arm chest flyes?
You can program single-arm flyes in one of two ways; either as a primer movement before your chest workout begins or as a finisher at the end. Both are valid — and you can even do both in the same session — so it’s really up to you.
How much weight can I lift on the single-arm chest flye?
Flyes limit your load more than presses. Single-arm exercises are similar. So, a single-arm flye will greatly diminish the amount of weight you can work with. The trade-off, though, is that all of the tension goes directly where you want it; right onto your pecs.
Featured Image: Ajan Alen / Shutterstock
