The chest, known technically as the pectoralis major, or pecs for short, makes up the major mass on the front of your upper body. As a large muscle group, it has a lot of areas to focus on: upper, lower, inner and outer. Developing the outer pecs is important for developing wide, impressive pecs . . . think Arnold Schwarzenegger back in the day. To really build the outer pecs, you need to perform weighted exercises that place a lot of stretch on the pecs. One of the best exercises for placing stretch on the pecs is dumbbell flyes. Be sure to perform these with just a slight bend in your elbows so that your arms are almost straight during the movement. Also, go as low as possible in the bottom position . . . again, think Arnold. This works to target the outer-pec muscle fibers, which will build up to add more width to your chest.
WHEN TO GO WIDE
To focus on the outer muscle fibers of the pectoralis major, do dumbbell flyes after doing major chest mass builders, such as bench presses and dumbbell presses.
FORM AND FUNCTION
The pectoralis major is composed of two major heads. The clavicular head, or upper pecs, starts on the clavicles (collar bones) and attaches to the humerus (upper-arm bone); the sternocostal head, or lower pecs, starts on the sternum and also attaches to the humerus. When the pectoralis major contracts, it moves the upper arm in numerous directions — such as toward the center of the body (adduction), during flyes and presses; forward (flexion), during reverse-gripbench presses; and down (extension), during pullovers.
