Chest Day? The underhand cable fly exercise primarily works the following muscles: Pectoralis major (chest): This is the main muscle targeted by this exercise, specifically the upper and middle portions of the chest. Anterior deltoid (front shoulder): This muscle assists in bringing the arms together in front of the body. Triceps brachii (back of the upper arm): These muscles help stabilize the elbows during the movement. Trapezius (upper back): This muscle helps maintain proper posture during t

Cable Fly: Muscles Worked, Alternate, Variations