Reverse Butterfly Exercise: Technique, Muscles Worked, and Benefits for Your Back

How to do butterfly exercise in gym for back?

The "butterfly" exercise, commonly known as the pec deck fly, primarily targets the chest muscles (pectorals). For targeting back muscles, specifically the posterior deltoids and upper back, the exercise you're likely thinking of is the reverse butterfly or rear delt fly machine.

Understanding the "Butterfly" Exercise

The exercise most commonly referred to as the "butterfly" in a gym setting is the Pec Deck Fly machine. This machine is designed to isolate and work the pectoralis major (chest muscles). Users sit with their back against a pad, gripping handles or pads that are then pushed together in front of the body, mimicking a "hugging" motion. This movement primarily involves horizontal adduction of the humerus, which is the primary function of the chest muscles. Therefore, the traditional "butterfly" exercise is not a back exercise.

The "Reverse Butterfly" for Back Muscles

If your goal is to target back muscles with a similar "butterfly" motion, you are referring to the Reverse Butterfly or Rear Delt Fly machine. Many modern pec deck machines are dual-function and can be adjusted to perform both the chest fly and the reverse fly. This exercise specifically targets the posterior deltoids (the rear head of your shoulder muscles) and secondarily engages the rhomboids and trapezius (upper back muscles).

How to Perform the Reverse Butterfly (Rear Delt Fly)

Performing the reverse butterfly correctly is crucial for maximizing muscle activation and preventing injury.

Setup:

• Adjust the Machine: Sit facing into the machine, with your chest against the pad. If it's a dual-function machine, ensure the arm levers are adjusted to allow for a wide, comfortable range of motion when reaching forward. The handles should be positioned so that your arms are extended forward and slightly bent, with your hands roughly at shoulder height.
• Seat Height: Adjust the seat height so your shoulders are aligned with the machine's pivot point. Your arms should be relatively parallel to the floor.
• Grip: Grasp the handles with a neutral grip (palms facing each other) or an overhand grip, depending on the machine and your comfort. Your elbows should have a slight bend throughout the movement; avoid locking them out.

Execution:

1. Starting Position: With your arms extended forward and a slight bend in your elbows, ensure your shoulders are pulled back and down (scapular depression and retraction) to engage the upper back, rather than shrugging your shoulders.
2. Concentric Phase (Pull): Exhale as you slowly pull the handles apart and backward, squeezing your shoulder blades together. Focus on initiating the movement from your rear deltoids and upper back, not just your arms. Imagine pulling your elbows back as far as possible.
3. Peak Contraction: Pause briefly at the end of the movement, feeling a strong contraction in your rear deltoids and between your shoulder blades.
4. Eccentric Phase (Return): Inhale as you slowly and controlledly allow the handles to return to the starting position. Resist the weight as it moves forward, maintaining tension on the muscles. Do not let the weights clang together.
5. Maintain Posture: Keep your chest pressed against the pad and avoid arching your lower back or using momentum.

Common Mistakes to Avoid:

• Using Too Much Weight: This often leads to using momentum, shrugging the shoulders, or excessive arm involvement, reducing the effectiveness for the target muscles.
• Rounding the Back: Keep your chest pressed firmly against the pad and maintain a neutral spine.
• Locking the Elbows: Always maintain a slight bend in the elbows to protect the elbow joint and keep tension on the muscles.
• Shrugging the Shoulders: Avoid letting your shoulders creep up towards your ears. Keep them depressed and retracted.
• Excessive Arm Movement: Focus on the squeeze of the shoulder blades and the pull from the rear deltoids, rather than just swinging the arms.

Muscles Worked by the Reverse Butterfly

The reverse butterfly is an excellent isolation exercise for the posterior chain of the shoulder and upper back.

• Primary Muscles:
  • Posterior Deltoid: The main target muscle, responsible for shoulder horizontal abduction and external rotation.
• Secondary/Synergistic Muscles:
  • Rhomboids (Major & Minor): Located between the shoulder blades, assist in scapular retraction.
  • Trapezius (Middle & Lower Fibers): Assists in scapular retraction and stabilization.
  • Rotator Cuff Muscles: Act as stabilizers during the movement.

Benefits of Incorporating Reverse Butterfly into Your Routine

Including the reverse butterfly in your workout offers several significant benefits:

• Improved Posture: Strengthens the muscles that pull the shoulders back, counteracting the common "rounded shoulder" posture often associated with desk work and excessive chest training.
• Shoulder Health and Stability: Balances the development of the shoulder girdle. Strong rear deltoids and upper back muscles are crucial for overall shoulder stability and can help prevent injuries.
• Balanced Muscular Development: Many individuals over-train the chest and anterior deltoids, leading to muscular imbalances. The reverse butterfly helps create a more balanced and aesthetically pleasing physique.
• Enhanced Performance: A strong posterior chain is vital for many athletic movements, including throwing, pulling, and pressing.

Programming Considerations

• Placement: The reverse butterfly can be performed on a back day, shoulder day, or as part of an upper body workout. It often serves as an excellent warm-up for more complex compound movements involving the shoulders or a finishing exercise to isolate the rear deltoids.
• Sets and Reps: Aim for 2-4 sets of 10-15 repetitions. Due to the smaller muscle groups involved, higher rep ranges are often effective for building endurance and muscle hypertrophy.
• Load: Focus on controlled movement and muscle contraction rather than lifting heavy weight. Light to moderate loads are typically sufficient.

Safety and Best Practices

• Listen to Your Body: If you feel any sharp pain, especially in your shoulders, stop the exercise immediately.
• Warm-up: Always perform a general warm-up (e.g., light cardio) and specific warm-up sets with light weight before attempting working sets.
• Controlled Movement: Avoid jerking or using momentum. The slower and more controlled the movement, the more effective it will be.
• Breathing: Exhale during the concentric (pulling) phase and inhale during the eccentric (returning) phase.

Conclusion

While the traditional "butterfly" machine targets the chest, the reverse butterfly or rear delt fly is an excellent and effective exercise for building strength and size in your posterior deltoids and upper back muscles. By understanding the correct form and muscle activation, you can safely and effectively incorporate this exercise into your routine to improve posture, enhance shoulder health, and achieve balanced muscular development.