Bayesian Fly

So-called fly exercises are popular exercises for isolating the chest muscles as much as possible. The main function during this exercise is pulling the upper arms forward using the pectoralis major. Because the arms maintain the same curve throughout the movement, the triceps are required much less than during the bench press. The biceps must nevertheless be kept under constant tension to hold the arms in a slightly bent position.

Flyes can be performed with dumbbells, machines, or cables.

An advantage of the cable and machine variations is the constant tension that is maintained even at the end of the exercise. In the lying dumbbell variation, you lose this tension at the end of the movement.

In the Bayesian fly , the hands are held with the palms facing down (pronated) instead of facing inward.

Besides the standing variation, the exercise can also be performed seated or lying on a bench. The seated and lying variations have the advantage that you need to use your core less to maintain your position.

Opinions vary regarding the correct height of the hands in the end position. The cables can be brought to a point at chest height or lower. The starting position of the pulley can also vary. For example, it can be attached at the highest point or at shoulder height, which naturally affects the angle of the cable. Maintaining a higher end point often means greater involvement of the shoulders. This may also relatively increase the involvement of the (smaller) upper part of the chest muscles. Varying the angles can ensure that you alternately target these different parts of the muscle and continue to provide sufficient stimulus for growth.

Bayesian Fly execution

Place the pulleys of the cable machine at the correct height (shoulder height or higher). Make sure that the same weight is set on both sides.

Stand or sit properly in the center. For the standing variation: Place one foot well forward and at hip or shoulder width. Your upper body is tilted slightly forward.

Bring your hands (with the palms facing down!) outward until your arms are almost horizontal. Keep the elbows slightly below shoulder height (starting position). Keep your arms slightly bent and maintain this curve throughout the movement.

Bring your hands together as if embracing a tree.

Cross your hands over each other at the end of the movement to increase the range of motion. Pull your hands through until your wrists or forearms cross.

Controlledly return your hands to the starting position.

Bayesian Fly

Active muscles:

Pectoralis major (large chest muscle)
Anterior deltoid (front fibers of the shoulder muscle)
Serratus anterior
Coracobrachialis (raven's beak arm muscle)

Stabilizing muscles:

Rotator cuff (stabilizing shoulder muscles, supraspinatus, subscapularis, teres major, teres minor)
Biceps brachii
Serratus
Trapezius
Triceps brachii
Latissimus dorsi
Core muscles

Bayesian Fly technique

One of the most common mistakes in this exercise is bending and extending the arms. Do not extend the arms when bringing the hands backward; keep them under tension. This prevents you from having to bend them extra again on the way forward and thereby prevents excessive involvement of the biceps.

Another common mistake is wanting to perform a fly, but turning it into a cable chest press. This is even more likely with the Bayesian fly because the hands are also directed with the palms down, as in the bench press (instead of inward as in normal flyes). The resulting incorrect movement is more of a forward push, as in the bench press, instead of an embracing movement.

As mentioned, you can turn a cable fly into a cable crossover fly by letting the hands cross each other. This can make balancing the exercise more difficult. Because of the width of the hands and handles, one arm will have to pass considerably underneath or over the other. This should therefore be done alternately. Crossing the hands consequently makes the exercise technically more difficult and can distract from proper execution.

Keep the elbows below shoulder level in the starting and ending positions. This is to prevent excessive involvement and a potentially injury-prone shoulder position.

Keep your upper body stable during the standing variation and do not let it move forward and downward when the arms move forward (and upward on the way back). Keep it slightly tilted forward throughout the exercise. If necessary, reduce the resistance so that you can perform the exercise without this form of cheating.

Do not bring the elbows too far backward at the beginning and end of the movement. They should not go far beyond the torso. A safe starting point is to the torso. Depending on the mobility of the shoulder, you can move slightly farther back for a greater range of motion.

At a glance