Gorilla Fly Decline

Gorilla fly is inverted shoulder adduction. This exercise is a variation of the decline dumbbell chest fly and cable fly (high to low). This exercise involves the primary shoulder adductor, the pectoralis major. This exercise is performed with two dumbbells while lying face up on a decline bench.

The inverted position allows the lifter to perform the movement executed in a cable fly (high to low) with dumbbells against gravity.

The concentric portion of the lift is a combination of horizontal shoulder adduction, shoulder adduction and elbow extension. The concentric portion involves the lifting of the weight. The eccentric portion is horizontal shoulder abduction, shoulder abduction and elbow flexion during the descent of the weight.

The purpose of the gorilla fly is to strengthen the pectoralis major while promoting hypertrophy (increases in size) of this muscle.

Gorilla flyes increase the size and strength of the upper (clavicular) and lower (sternocostal) heads of the pectoralis major. The downward phase entails a stretch of the pectoralis major as the shoulders are abducted, resulting in significant activation of the pectoralis major fibers as the arms adduct.

Gorilla flyes stress the fibers of both upper and lower regions of the pectoralis major and can help define the separation between left and right pectoral muscles.

Performing this exercise at a decline and with greater emphasis on shoulder adduction provides a variation in chest flyes that targets different muscle fibers of the pectoralis major. Stressing muscle fibers from different angles optimizes strength and hypertrophy of the trained muscle group.

The latissimus dorsi, long head of the triceps and anterior deltoid are also activated in this movement.

Gorilla flyes serve as a valuable exercise to improve aesthetics of the pectoral muscle.

The pectoralis major is a large, fan-shaped muscle that spans across the chest, forming the front portion of the axillary fold (arm pit). It is divided into two parts: clavicular and sternal. Its origin is located at the sternal end of the clavicle, the sternum, rib cartilage (ribs 1-6 [or 7]), and the aponeurosis of the external oblique. The fibers of the pectoralis major converge at the point of insertion located at the greater tubercle of the humerus. The pectoralis major aids in pushing movements as the shoulder adducts the arm against resistance. The shoulder horizontally adducts in the initial portion of the lift followed by adduction as the dumbbells are lifted directly over the body.

The inverted position of this exercise targets both the sternocostal and clavicular heads of the pectoralis major. Gorilla flyes are an effective training tool for developing and defining the entire chest.

The latissimus dorsi is a broad, flat, and triangular-shaped muscle of the lower back. When defined, the “lats” form a “v” shape of the torso as they angle toward the waist. The latissimus dorsi is a primary shoulder adductor. Its origin is located along the spines of the lower six thoracic vertebrae, lower 3 to 4 ribs, and iliac crest of the pelvis. Its insertion spirals around the teres major as it inserts into the intertubercular groove of the humerus.

The triceps brachii is located on the back of the upper arm, originating at the shoulder and inserting in the elbow joint. It consists of three heads, the long, medial and lateral head. The medial head lies beneath the long and lateral head. The long head origin is located at the infraglenoid tubercle of the scapula (shoulder blade). The original of the lateral head is located at the posterior shaft of the humerus. The medial head origin is located at the radial groove of the posterior humeral shaft.

The long and lateral heads make up the “horseshoe” portion of the triceps. All three heads merge, sharing insertion into the olecranon process of the ulna, located at the elbow joint.
The triceps brachii extend the elbow joint. The long head assists in arm adduction when executing this movement.

The deltoid is a thick, multipennate muscle that forms a curtain around the shoulder. It is the primary muscle involved with arm abduction and the anterior fibers are a primary shoulder flexor. The anterior deltoid is a primary synergist of the pectoralis. When developed, the deltoids give the shoulder their round shape. The origin of the deltoid is located at the insertion of the trapezius, lateral third of the clavicle and the acromion spine of the scapula. Its insertion is located at the deltoid tuberosity of the humerus.

A synergist of the latissimus dorsi, the teres major is a thick muscle located underneath the teres minor. Along with the latissimus dorsi, it also helps to form the posterior wall of the axilla. This muscle assists with shoulder adduction during this exercise. Its origin is located at the posterior surface of the scapula at the inferior angle. Its insertion is located at the crest of the lesser tubercle on the anterior humerus (its tendon fused with that of the latissimus dorsi).

The anconeus is a short, triangular muscle located at the elbow joint. Its origin is located at the lateral epicondyle of the humerus. Its insertion is located at the lateral aspect of the olecranon process of the ulna. The anconeus assists the triceps brachii during elbow extension.

Like the anterior fibers of the deltoid, the coracobrachialis is a synergist pectoralis major with horizontal shoulder adduction. It is a small muscle originating at the coracoid process of the scapula and inserting half way down the shaft of the humerus.

The serratus anterior, rhomboids, biceps brachii and rotator cuff muscles are important stabilizers in this exercise for the shoulder and elbow joint. The abdominal muscles stabilize the torso in the inverted position while the wrist flexors stabilize the wrists.

Cable chest flyes (high to low), decline dumbbell chest fly, incline dumbbell chest fly, (flat bench) dumbbell chest fly, machine chest fly.

Strategically incorporating cable flyes (high to low) into your training regimen will complement the strength and hypertrophy gains of this exercise. Cable flyes (high to low) follow the same movement pattern, but from a standing position. Performing chest fly variations (e.g. dumbbell chest fly) also complement the gains achieved from this exercise.

To minimize negative stress on your shoulder joint, do not allow the upper arms and elbows to drop below shoulder level on the descent.

Utilizing a spotter can ensure the safety of this exercise. They can also monitor your technique.

Focus on the concentric portion of the contraction, concentrating on “squeezing” as arms adduct and dumbbells are lifted upward.

Emphasis on eccentric contractions, prolonging the eccentric portion of the contraction, may also be incorporated in a training program focused on increasing strength. This should be implemented accordingly and with adequate muscle recovery as eccentric contractions cause substantial damage to muscle tissue.

It is important to note that your repetition and set volume will depend on your goals (e.g. strength, hypertrophy, muscular endurance). It is also important to allow adequate recovery days in between chest and triceps training to allow muscles to repair.

Lowering the dumbbells too low should be avoided as it results in excessive shoulder abduction against resistance, which can place great stress on the shoulder joint. Ensure that the upper arms do not pass the level of the torso when lowering the dumbbells. 1

Bouncing the dumbbells together at the top of the upward phase is unnecessary. Although the dumbbells will move closer one another as the elbows fully extend, it is not necessary for them to touch.

When initiating the lift to assume the starting position, swinging the dumbbells upward may compromise the biceps tendon if the dumbbells are heavier. When the set is complete, extending the shoulders from the lying position to lower the dumbbells to the floor can compromise the shoulder joint. Dropping the dumbbells is also inadvisable as it is frowned upon and can damage the dumbbells and the facility. Sitting upward on the decline bench and extending elbows to place weights on each side of the bench is a better alternative for the safety (and reputation) of the lifter.

It is very common to observe an individual arching their back in efforts of lifting the weight with more ease. This technique should only be performed by weightlifting professionals and can compromise the safety of lifters.

Lifting heavier weight without a trained spotter. With moderate to heavy weight loads, a trained spotter should monitor the lifter throughout their set for optimal safety.

1. Reinold MM, Gill TJ, Wilk KE et al. (2010). Current concepts in the evaluation and treatment of the shoulder in overhead throwing athletes, Part 2. Sports Health. 2(2):101-115.

If proper technique is not adhered to (e.g. arching of the back, lowering the upper arms past the level of the torso, dropping the weight quickly instead of controlling the descent on the eccentric portion of the lift), the likelihood of injury increases.

If proper technique and recovery are not adhered to, impingement syndrome, rotator cuff injuries, biceps tendonitis/biceps tendinosis, pectoralis major tears and/or glenoid labrum tears may result. It is best to avoid exercises that involve horizontal shoulder abduction against resistance on the eccentric phase (e.g. bench press, gorilla fly, chest fly) when addressing impingement syndrome/rotator cuff injury unless advised by a physical therapist.