Bench Press: Muscles WorkedAs "handsy" creatures, we benefit from strong shoulders and arms. We also seem particularly drawn to big chests and big arms as a marker of size and strength. Whereas “arm training” is not a top priority for general strength, training your chest means training the functionality of your shoulder and a wide range of movements, making the bench press—when combined with the overhead press—a big part of the comprehensive strengthening of your upper body.
Bench Press: Muscles Worked
One can trace a direct line to bodybuilding aesthetics—favored by action heroes and superhero comic book artists—from the classical aesthetics of ancient Greeks and Romans, where visible abs and big pecs have been a consistent identifying trait of a (mostly nude) hero image. The Greeks favored an idealized male image even on the battlefield. Bronze armor from the fourth and third centuries B.C. have stylized upon them muscular chests and visible abs, earning them the name of muscle cuirass. Roman officers would later adopt the muscle cuirass, and paintings often depict ancient superheroes like Achilles wearing the stylized breastplate; superman and his tights were not far behind. The muscle cuirass and tall helmets might cause opposing forces to believe they are being assaulted by “men of bronze.” They reveal a certain ideal of the heroic male muscular physique with which we are still bombarded today.
That ideal continues to draw young men to the gym’s bench press section to work on building a bigger chest. But, the bench press is also one of the four big barbell lifts that we use for strength.
It turns out that within the contrivances of barbell training there exists a confluence, where those training for strength development, sports performance, and pure aesthetics have a meeting of the minds. Because, while the bench press helps to build a bigger chest and strong arms—the beginnings of your own muscle cuirass—it also makes the cut as one of our four main lifts for the sheer potential it carries to develop upper body strength.
What the bench press gives us is trainability—the potential for ongoing, long-term, consistent growth—and raw upper body strength. The trainability of a lift depends on whether one can make steady progress for a long time and how well the lift contributes to the desired systemic stress of training. We don’t just want to make individual muscles stronger, we want to lift in ways that accumulate fatigue and trigger a whole-body hormonal response. Big, basic lifts that train large muscle groups and multiple joints are often trainable lifts.
The bench press is usually thought of as a chest exercise, which is an accurate but aesthetic categorization. Your chest gets most of its shape and definition from the pectoralis major, one of the prime movers of the bench press. Functionally, however, the bench press is a shoulder and arm exercise, training movements around the shoulder and elbow.
Any time you train the shoulder in multi-joint movements, requiring control of an external load—as opposed to isolated, machine exercises—you employ not just the primary movers, but also a supporting cast of muscles, whose job it is to keep your arm firmly in the ball and socket of the glenohumeral joint.
Ball and socket joints allow for multi-plane movement. You might think of a contrasting hinge joint—like your knee or elbow—as allowing movement in one plane, the way a door swings open and closed but does not move in any other direction. A ball and socket joint fits together like a mortar and pestle. If the hinge joint is a two-dimensional joint, the ball and socket is in 3D, allowing not just flexion and extension of the joint, but also abduction and adduction (moving structures away from or toward the body’s midline, respectively) and internal and external rotation. These many degrees of freedom mean that there are few bony structures actually keeping your arm attached to your body.
Humans are handsy creatures, benefiting from strong shoulders and arms. We also seem particularly drawn to big chests and big arms as a marker of size and strength. Whereas “arm training” is not a top priority for general strength, training your chest means training the functionality of your shoulder and a wide range of movements, making the bench press—when combined with the overhead press—a big part of the comprehensive strengthening of your upper body.
The Bench Press: Actions and Muscles Trained
Let’s go through the basic movement of the bench press. The lifter will take a grip that is shoulder width or slightly wider. (A good rule of thumb is to place your hands a thumbs-length from the edge of the knurling, adjusting so that the forearms are vertical at the bottom of the bench press.) With the grip in place, the lifter unracks the bar (with straight arms) and moves it to a position over the shoulder joint. Either before or after unracking the bar, the lifter must lift the chest—rotating it upward, like trying to touch sternum to chin—and pinch the shoulder blades back and together, creating an arched position on the bench. Pressure from the legs will keep the lifter’s butt on the bench and prevent it from sliding away from the shoulders, helping to provide stability and some mechanical efficiency to the movement. (Read more about building the bench press bridge here.) The lifter will lower the bar to touch at about mid sternum, a few inches lower on the chest than the shoulder joint. At this bottom position, the shoulders are extended, the elbows are flexed, and the humerus is rotated laterally, pointing the elbows more toward the feet than away from the body. To return the bar to the starting position, the prime movers of the bench press flex the shoulder joint, medially rotate the humerus, and extend the elbows to the lockout position. This takes the main efforts of the pectoralis major, the anterior deltoids, and the triceps brachii, supported by muscles of the shoulder, the neck, and upper back. Let’s look first at the primary movers.
The pectoralis major is a large, fan-like muscle. Its origin traces along the medial, sternal, side of the clavicle (collar bone) then down, attaching to the upper two-thirds of the sternum with tendinous connections to those ribs that also attach to the sternum. If you were to follow these origin points with your finger, you would make a rough and blocky “C” shape with the open end facing out toward your shoulder. The muscle fibers form a fan pattern, pointing toward the muscle’s attachment on the outer (lateral) lip of the humerus’ bicipital groove.
The pectoralis major’s primary functions with respect to the bench press are shoulder flexion (moving your elbow from behind you to in front of you), shoulder adduction (what you do when you pull your arms from the widespread Vitruvian Man position toward your body with arms at your sides), and medial rotation of the humerus (turning your arms so that your elbows go from pointing at your feet to pointing away from your trunk). The concentric portion of the bench press (the pressing part) begins primarily with shoulder flexion and the medial rotation of the humerus.
The pectoralis major is trainable because of its size and the mechanical advantage you get from its growth. The pectoralis major is a large muscle, and large muscles get stronger longer than smaller muscles. In addition, as the pectoralis major grows, the bench press will tend to improve for purely mechanical reasons, since the size and shape of one’s chest defines the bottom position of the lift. A bigger chest will reduce the overall range of motion and will improve the angle of attachment between the pectoralis major and where it pulls on the humerus, flexing the shoulder and medially rotating the upper arm. Leverage makes the pecs’ job easier, the bigger the muscle gets. So, you get a double bonus from training your bench press.
The deltoid muscle covers the glenohumeral joint, originating on the edge of the spine of the scapula (posterior deltoid), the top of the shoulder at the lateral acromion (lateral deltoid), and the clavicle (anterior deltoid). Each section attaches to the deltoid tuberosity of the humerus. Each section also provides a different function for the shoulder because the angles at which they pull on the humerus move it in different ways. The anterior section of the deltoid shares the flexing of the shoulder joint and the medial rotation of the humerus in the socket with the pectoralis major. Whereas the overhead press will train the entirety of the deltoid muscle, the anterior deltoid is primarily involved in driving the bar of the chest in the bench press.
Grip width can change the movement around the shoulder and elbow in a bench press. A wider grip will involve a more extended elbow and a more abducted shoulder. Wider grips also tend to move the arm closer to ninety degrees of abduction, possibly contributing to shoulder injuries from bench pressing. A narrower grip creates a more flexed elbow, putting more emphasis on extending the elbow from the bottom fo the lift. The narrower the grip, the more the triceps have to work in the bench press. And those who have regularly performed close grip bench presses will recall that a too narrow grip limits how much weight you can lift. The moderate grip we advocate allows for a lot of movement around the shoulder joint and a non-limiting involvement of the triceps.
The triceps brachii is a three-headed muscle, primarily responsible for elbow extension. The heads of the triceps attach at the lateral part of the scapula below the glenoid cavity of the shoulder (the long head) and on the humerus (the lateral head on the upper half of the humerus and the medial head below it and mostly covered by the long and lateral heads). Each of the three heads inserts at the olecranon process of the ulna, the pointy part of your elbow. The long head, by crossing the shoulder joint has a proximal function, stabilizing the head of the humerus when the shoulder is adducted (pulling the humerus into the joint) and extending the arm at the shoulder. (Which is why the Rolling Dumbbell Extension is one of the best accessory lifts for building big triceps.) All three heads of the triceps brachii extend the elbows.
In the bench press, the triceps are the primary movers that lock the bar out into the finished or starting position of the movement. The bench press does not train the full range of motion of the triceps. As mentioned above, the long head of the triceps extends the shoulder and the amount of involvement of the triceps over the complete range of motion of the bench press changes with grip width. Your elbows are not fully flexed at the bottom of the bench press. Ideally, they are held at around 90 degrees of flexion with your forearms vertical when viewed from your head or your feet. For a bigger range of motion around the triceps, the overhead press is a better lift. But the bench press plays an important role in developing your triceps in that it helps to overload them with heavier weights. You will handle more weight on the bench press than you will with your overhead press or accessory lifts. Overloading the triceps’ function prepares them for heavier pressing weights and helps contribute to the bench presses’ value as a systemic stressor. (Read more: Homeostasis: A Framework for Strength Gains.)
The coordinated movement of elbow extension with the medial rotation of the humerus and shoulder extension is also a common and important movement in many sports: throwing things or hitting things, pushing, gripping and controlling, and pulling things to your body all involve the use of the muscles around the shoulder girdle and all benefit from a powerful bench press.
Several muscle groups limit sudden or forceful movements that might cause a translation of the humerus out of the ball and socket joint, leading to injury. The rotator cuff muscles get their name because they insert around the humerus forming a “cuff” whose main job is to keep your arm in its socket. Those that also provide for the external rotation of the humerus, attaching on the posterior side of the arm, will act to help limit the medial rotation of the arm by the pectoralis and anterior deltoids during the bench press. These muscles get more thoroughly trained in their primary functions during the overhead press, which suggests that the overhead press promotes shoulder health in anyone trying to build a big bench press. The lats help control elbow position during the concentric phase of the bench press, maintaining an elbow position that is slightly lower (on the foot side) of the bar, preserving the correct bar path and helping to keep the humerus from 90-degrees of abduction, which can lead to impingement of the rotator cuff muscles.
The Chest Up Position
When you set up for the bench press, you lift your chest and pull your shoulder blades back, giving you an arched position on the bench press and creating a flat, stable surface against which to push as you drive the bar to the lockout position. When you arch your back in the bench press, you are both raising your chest and the touchpoint that marks the bottom of the movement, shortening the distance vertically. You are also pulling your shoulder horizontally closer to that touchpoint. Posteriorly, the trapezius and rhomboid muscles retract your scapula, and the muscles of your upper back pull your chest up while your neck muscles contract and help create stability. Anteriorly, the pectoralis minor pulls the rib cage up. The arched position improves the efficiency of a necessarily inefficient movement.
Trunk and Legs
Extraneous movement of the bar or body during the bench press means that some force that should have gone to the bar got lost along the way. The lifter’s trunk and legs help keep the lifter’s body firmly on the bench, improving stability and preventing force from being lost to unwanted movement. Tight abs and a solid bridge help the lifter stay stable on the bench press. Many lifters prefer to bench press with their belt on for exactly this reason.
Feet pushing against the floor help keep the lifter’s butt in place on the bench. The legs should be actively engaged, as the pressing motion will tend to flatten out the lifters arch, moving their hips and butt away from their shoulders. When this happens, the lifter loses stability, and the bench press becomes more difficult than it needs to be.
The bench press is the king of lifts for raw upper body strength. The application of that strength and comprehensive training of the upper body for general strength, aesthetics, and overall shoulder health requires more than just benching. That is why we overhead press, chin, and use movements like the barbell row. But a strength program without the bench press will be limited in how well it develops useful upper body strength. So, lie down, take a load off, and build yourself a bigger, stronger chest.