Although unilateral training is not inherently better than bilateral training, many movement patterns in sports and everyday life are unilateral.
A meta-analysis published in Frontiers in Physiology proved that we must do unilateral training to improve unilateral power patterns and vice versa (1). This leads us to the conclusion that bilateral training alone is not enough.
After 10 years of working out and coaching people, I can say that pecs are not just for aesthetics. A well-developed chest also means better breathing and greater upper body strength.
In this article, I’ll address one of my favorite unilateral chest exercises — the one-arm cable chest fly. You’ll also learn about how to do it, its benefits, mistakes, and alternatives.
How To Do One Arm Cable Chest Fly
Here is a step-by-step explanation of how to perform one-arm cable chest flyes with a flawless form:
Step One — Setup
First, you need to set the pulley at an appropriate height. Some prefer chest height, while others favor shoulder height. In my experience, there is no significant difference in muscle engagement, so go with the option that suits your biomechanics.
Then, connect a D-hand attachment to the pulley. Stand sideways to the machine and grab the handle by extending your working arm to the side. Your upper arm should be parallel to the floor. Take a few small, lateral steps to engage the weights and create tension.
Ensure your shoulder is relaxed and not raised, maintaining a neutral position. Place your non-working hand on your hip throughout the exercise.
Your torso should remain upright and your chest proud. Avoid leaning or twisting your torso to isolate the chest muscles effectively during the exercise.
Pro Tip: Engage your core and pay attention to your spine alignment.
Step Two — Perform the Fly
Now, it’s time to pull the weight horizontally.
Once you are ready, bring your arm across your body while limiting the movement to the shoulder joint. Do not stop when you reach the midline; extend the motion a little more — stop when the upper part of your biceps touches the outer pecs.
Keep your elbow slightly bent throughout the range of motion.
Pro Tip: Contract your chest in the fully shortened position.
Step Three — Return to the Starting Position
Slowly reverse the movement to return to the starting position. You must control the weight. If the cable pulls you back, it’s either due to excessive weight or a lack of focus.
Pro Tip: Start the next rep just before the weight touches the stack to maintain constant tension.
Watch the following video where Filip Maric demonstrates the One Arm Cable Chest Fly exercise technique:
Muscles Worked During One Arm Cable Chest Fly
Several muscles work synergistically to help you perform the one-arm cable chest fly, including:
- Pectoralis Major: This is the primary muscle targeted during the exercise. It brings the arm across the body (horizontal shoulder adduction).
- Anterior Deltoid: The front part of the deltoid muscle assists in shoulder flexion and stabilization.
- Serratus Anterior: This muscle, together with pectoralis minor, stabilizes the shoulder blade and assists in the protraction of the scapula.
- Biceps Brachii: Although not the primary muscle targeted, the biceps brachii is a dynamic stabilizer. Bicep muscles help flex the elbow and control the arm’s movement.
- Core: The core stabilizes your trunk and works isometrically, but I wouldn’t count this exercise toward my ab workout.
Benefits of One Arm Cable Chest Fly
Still wondering how you will benefit from a one-arm cable chest fly? Let me highlight some benefits that make this exercise unique:
Bench press, the most popular chest exercise, is a compound exercise that stresses most of your upper body. Such exercises are essential for building strength and should be the foundation of every well-balanced workout program.
However, you need isolation exercises as well. The one-arm cable chest fly allows focused muscle engagement. It can promote symmetrical muscle development and correct imbalances.
Improved Range of Motion
The cable fly offers an extended range of motion compared to barbell and dumbbell bench presses, allowing for a deeper stretch and better muscle contraction. Range of motion is very important for athletes, especially those who demand so much from their upper body — for example, tennis players, baseball pitchers, and quarterbacks.
Another crucial point to bear in mind is to avoid twisting your torso. While it might appear to extend the range of motion, it will ultimately compromise muscle stimulation.
Reduced Shoulder Strain
Free-weight chest exercises put considerable strain on the shoulders. The cable machine limits strain on the shoulder joints and delivers constant tension on the target muscle throughout the movement.
Tips For Performing One-Arm Cable Chest Fly
Embracing these tips can heighten the efficiency of unilateral cable chest fly:
Gradual Weight Progression
Start with lighter weights and gradually increase the resistance. Feel free to stick to lighter weights if you feel better pec activation that way.
Focus on Mind-Muscle Connection
Focus on contracting the chest rather than just moving the weight. You must feel your pecs working throughout the ROM, not your biceps or shoulders.
I suffered a sternocostal joint injury doing dips, and after a few months, I experienced a setback doing a one arm cable chest fly because I skipped warm-up.
So, always do dynamic stretches and light exercises before starting a workout to increase blood flow and improve mobility.
Common Mistakes During One Arm Cable Chest Fly
Knowing common mistakes can help you perform an exercise with precision and awareness:
One of the primary errors during the one-arm cable chest fly is the tendency to round the shoulders. Concentrate on keeping shoulders pulled back and down.
Also, don’t bend forward. Maintain a stable, upright posture.
Incorrect Elbow Positioning
This is one of the mistakes I noticed even those with years of gym experience make.
If you allow the elbow to flare out to the side, bend the elbow too much, or keep the arm straight, you will de-emphasize the pecs and primarily engage the biceps, shoulder, or other upper body muscles.
Lack of Control During The Movement
Usually, lack of control during the movement stems from using too much weight. However, that is not always the case.
Rushing through a set can lead to injuries and suboptimal muscle activation. Avoid relying on momentum to lift the weight, and stick to a strict range of motion.
Best One Arm Cable Chest Fly Alternatives and Variations
I want to share with you my favorite alternatives and variations that can further enhance your chest workout:
Low to High Cable Fly
The low-to-high cable fly is my go-to for targeting the upper chest. Although the pectoralis major is one muscle, multiple attachment points make it move like it has several heads.
By adjusting the line of pull and the angle of your body, you can effectively isolate and stimulate different parts of the pecs, promoting muscle growth and definition.
- Set the cable machine pulleys to the lowest position.
- Choose the weight and attach D-handles.
- Stand in the center of the cable machine.
- Grab the handles with an overhand grip and step forward to engage the weight.
- Bend your elbows slightly and stand with your feet shoulder-width apart.
- Squeeze your chest and exhale as you bring the handles up and together at shoulder level.
- Pause at the top of the movement, then slowly lower the handles back to the starting position.
Pro Tip: Try a single-arm variation to reap the benefits of unilateral movement.
Dumbbell Chest Fly
The dumbbell chest fly is a classic isolation exercise that targets the chest. The shoulders and arms act as secondary muscles.
This exercise is ideal for beginner and advanced lifters. It works the pectoral muscle fibers through a full range of motion, ensuring a deep stretch and contraction.
However, be careful because you can injure your pecs and shoulders if you use dumbbells that are too heavy.
- Lie on a bench with a dumbbell in each hand.
- Extend your arms above the chest.
- Move the dumbbells out to the sides in a broad reach.
- Keep a slight bend in the elbows.
- Bring the dumbbells down until you feel a stretch in your pecs, then squeeze the chest to return the dumbbells to the starting position.
Pro Tip: Explore decline and incline variations to take advantage of different angles. Changing angles is good for preventing plateaus.
Machine Chest Fly
If you are afraid to use free weights because of a recent injury or poor technique, then the machine is the best choice.
The chest fly machines provide stability and support throughout the guided motion. You will find it in almost every gym.
- Sit on the machine with your back against the pad and hold the handles with a neutral grip.
- Press the handles together in front of your chest, slightly bending the elbows.
- Slowly return to the starting position until your chest muscles stretch entirely.
- Squeeze the chest muscles to bring the handles back together.
Pro Tip: Make sure to adjust the seat height because improper height will impair your posture and, thus, the effectiveness of this exercise.
Can beginners do the one-arm cable chest fly?
Yes, a one-arm cable chest fly is a beginner-friendly exercise. It’s great for building chest strength and stability. This exercise allows beginners to focus on proper form and muscle engagement without the complexity of heavier compound movements.
How often should you include this exercise in your routine?
The frequency of the one-arm cable chest fly in your routine depends on your overall training program and goals. Generally, doing it 1-2 times per week alongside other chest exercises will promote balanced muscle development.
What should be the rep and set range for optimal results?
Aim for 3-4 sets of 8-12 repetitions per side for the best results. This number of sets and reps is optimal for muscle hypertrophy and strength gains. However, if you have a sport-specific goal, a significantly higher or lower rep range can also be useful.
Is it normal to feel more activation in one side of the chest during the exercise?
Yes, it’s quite common to feel more activation on one particular side during unilateral movements. This can be due to muscle imbalances, dominance of one side, or differences in form and technique. Keep in mind that it is practically impossible for both sides to be 100% the same, but the deviation should not be too significant.
Can the one-arm cable chest fly be incorporated into a home workout routine using resistance bands?
Absolutely! The one-arm cable chest fly can be easily adapted for a home workout routine using resistance bands. Simply anchor the resistance band to a sturdy surface and follow the same cable machine movement pattern.
I always encourage my clients to experiment with different exercise variations and techniques. That’s the way to keep your workouts challenging and effective. Incorporating the one-arm cable chest fly into your workout routine can take your chest training to the next level.
Always listen to your body to prevent injury and promote long-term progress. Let me know your thoughts about this unilateral exercise in the comments below.
- Zhang W, Chen X, Xu K, Xie H, Li D, Ding S, Sun J. Effect of unilateral training and bilateral training on physical performance: A meta-analysis. Front Physiol. 2023 Apr 13;14:1128250. doi: 10.3389/fphys.2023.1128250. PMID: 37123275; PMCID: PMC10133687.
- Calatayud J, Vinstrup J, Jakobsen MD, Sundstrup E, Brandt M, Jay K, Colado JC, Andersen LL. Importance of mind-muscle connection during progressive resistance training. Eur J Appl Physiol. 2016 Mar;116(3):527-33. doi: 10.1007/s00421-015-3305-7. Epub 2015 Dec 23. PMID: 26700744.
Article Updates Timeline:
Our editorial team experts constantly update the articles with new information & research, ensuring you always have access to the latest and most reliable information.
February 11, 2024
Filip Maric, PT