The human chest consists of two main muscles: the Pectoralis Major, which is the larger muscle stretching from the middle of the chest to the upper arm bone, and the Pectoralis Minor, which is smaller and connects the 3rd, 4th, and 5th ribs to the shoulder blade. The pectoralis major lies on top of the pectoralis minor and is the primary muscle targeted in most chest workouts. It's common to refer to these muscles simply as the "Pecs."
You can find exercises and information about other muscle groups on the Weight Training Main page.
The pectoralis major is the larger chest muscle, running from the sternum (middle of the chest) to the upper arm bone (humerus). Its main function is to move the upper arm forward. While the shoulder muscles lift the arms, the chest muscles bring them forward.
The pectoralis major is divided into three parts:
a) Pars Clavicularis – Upper Pectoralis Major
To target your upper chest, use incline bench presses or incline flies. The steeper the bench, the more the shoulders are involved. If the bench is vertical and you're pressing straight up, you're no longer working the chest—you're doing a military press, which targets the shoulders.
b) Pars Sternocostalis – Middle Pectoralis Major
This section is trained with any chest exercise where the weight is pressed directly out from the body, typically at a 90° angle to the torso.
c) Pars Abdominalis – Lower Pectoralis Major
This part can be activated with decline bench presses or chest dips on parallel bars.
The pectoralis minor is the smaller muscle located underneath the pectoralis major. Its main function is to pull the shoulder forward (scapular protraction). It's not heavily activated during bench presses but plays a bigger role in activities like swimming. Swimmers often have well-developed pectoralis minor muscles, which can give the appearance of a fuller chest near the shoulders. Unlike the pectoralis major, the pectoralis minor does not extend to the center of the chest.
When bench pressing, keep your shoulders stable and retracted (pulled down and back). This isn't because you want to avoid working the pectoralis minor—it's because lying on a bench restricts shoulder blade movement. If the shoulder blades move during pressing, it can affect stability and performance.
However, in bodyweight exercises like push-ups, your shoulder blades are free to move. Here, it’s fine to shrug your shoulders slightly during the motion, allowing more engagement of the pectoralis minor.
Swimming is also a great way to activate and strengthen the pectoralis minor.
