Major Muscle Groups Used in Bench Press

There's a reason the bench press is the quintessential chest exercise: Not only does it work your pectoralis major — or the big, obvious muscle in your chest — it's also a compound movement that lets you do more work in less time by working all the pushing muscles of your upper body at once.

The muscle that provides the most oomph to power a bench press is the pectoralis major, the large, beefy chest muscle that's readily visible on men who have well-developed chests. The pectoralis major is somewhat less readily visible on women, because much of it lies beneath the breasts.

However, your pecs aren't the only muscles at work during the bench press. Your synergists, or the other muscles that kick in to help make the movement happen, include:

The anterior deltoid: This is the front portion of your deltoid muscle, which sits atop each shoulder like a three-lobed cap. As you're lying down in the bench press position, it helps bring your arms in toward each other as you lift the weight — a movement known as transverse flexion.

If you're bench-pressing with your elbows held close to your body, your anterior deltoid also helps with shoulder flexion. This is a movement that, if you were standing, would look like swinging your arms forward at the shoulder. From the lying position, it's best described as swinging your arms up from the shoulder.

Triceps brachii: This is the meaty muscle on the back of your upper arm. Its primary job is straightening your arm at the elbow — a critical component of any pressing movement.

At the same time, all the muscles of your shoulder girdle engage to stabilize your scapula (shoulder blades) and your shoulders throughout the bench press range of motion.

You'll find numerous variations of the bench press that, depending on your fitness goals, might be used to develop different parts of the muscle or simply develop strength at different angles. One of the most common variations is doing the bench press at an incline (using an angled bench that places your head higher than your hips) or at a decline (this angled bench places your head lower than your hips).

In an interesting and useful analysis of the bench press movement, the experts at ExRX.net note that there's some controversy between researchers about exactly how much the incline and decline variations of the bench press change the muscle recruitment.

However, there is almost complete consensus that the incline bench press solicits more activity from the clavicular head of the pectoralis major. This is the part of the muscle that's highest on your chest. The incline press also causes your anterior deltoid to engage more powerfully.

The same analysis notes that the latissimus dorsi (a large, powerful pulling muscle in your back) engages more powerfully during decline presses, along with the long head of your triceps brachii.

During some barbell exercises, you can choose between an overhand grip (both palms facing down, toward your feet) or a mixed grip (one palm facing toward your feet, while the other faces away from your feet). That's not an issue during a bench press: For this exercise, you'll always hold the bar in an overhand grip.

However, not everybody agrees on how narrowly or widely apart your hands should be on the bar. In an interesting article on these variations, the American Council on Exercise asks a panel of three professional trainers to weigh in on the pros and cons of these grips.

Ultimately, the article concludes, your choice of grip comes down to which muscles you want to strengthen. If you want to emphasize involvement of your chest and anterior deltoids, the wide grip (placing your hands on the bar a little wider than shoulder-width apart) is more effective. However, this also places significantly more torque on your shoulders, which in turn increases your risk of injury and might require a more limited range of motion.

The ACE article also notes that if you want to emphasize involvement of your arms and place less strain on your shoulders, a narrow grip (placing your hands slightly closer than shoulder-width apart) is more effective — although it, in turn, places more stress on your forearms and wrists.

Is the bench press the single best exercise for your chest? According to a small independent study commissioned by the American Council on Exercise, the answer is yes. In the study, researchers from the University of Wisconsin, La Crosse's Department of Exercise and Sport Science recruited 14 men between the ages of 19 and 30 and tested their pectoralis major recruitment during five common weightlifting chest exercises and four body-weight chest exercises.

The exercises tested were the barbell bench press; bent-forward cable crossovers; seated chest press machine; incline dumbbell flies; pec deck (essentially, pectoral flies on a weight machine); dips; suspended pushups; stability-ball pushups; and standard pushups. Of these exercises, the barbell bench press had the most pec activation.

With that said, the "best" exercise is always the one that best suits your fitness goals and one that you're willing to do; both the pec deck and the bent-forward cable crossover were very close behind the barbell bench press, showing 98 and 93 percent of muscle activation, respectively, when compared to the bench press. The next most-effective exercise, the seated chest press machine, was relatively far back, showing just 79 percent recruitment when compared to the barbell bench press.

Read more: 10 Compound Moves for Greater Pump in Less Time

So how do you perform a bench press, anyway? You need a solid, stable weight bench with a rack on it — that is, reinforced pins that can hold the bar at, or near, the "up" position — plus a spotter, especially if you're just starting out. And, of course, you need the barbell and weight plates.

Depending on your fitness status and goals, doing a barbell bench press might present too much of a challenge for your shoulder mobility and the stability of your scapula, or shoulder blades — an integral part of any pushing or pulling motion.

If your shoulder stability or mobility are compromised, it's always best to speak to a medical or rehabilitation professional about which exercises you can or can't do, and through which ranges of motion. If doing the chest press is an important fitness goal for you, whether functionally or psychologically, a professional might be able to prescribe a series of exercises to help you build the stability and mobility you need to safely undertake this exercise. She might also clear you to do the bench press in a modified fashion.

Some of the modifications you might make to safely do this exercise include:

• Reducing the range of motion.
• Changing your hand position on the bar.
• Using dumbbells or elastic resistance bands instead of a barbell.

In addition to choosing a grip and range of motion that's safe and pain-free, there are a few other safety issues you can avoid with just a little forethought.

This first is setting up your bar. Although it might seem intuitive, not everybody loads the same amount of weight on both sides of the bar — make sure you do. And although it might be considered fashionable in some circles to lift barbells without weight collars at the end, or more convenient because you can thus switch out the weight plates more quickly, the safest practice is to always to add a weight collar on each side.

These spring-loaded clips lock the weight plates in place so that even if you let the bar tip to one side or the other, they won't shift position or fall off. That's not just a question of taking chunks out of the floor (or your gym buddy's feet) with falling weight plates; having the bar jerked from one side to the other as weight plates shift or slide off could seriously injure you.

Also, don't forget to take the weight of the bar itself into account when you're deciding how much to lift. The standard Olympic barbell that you'll use for most powerlifting exercises like this weighs about 45 pounds — so if you're a beginner who wants to bench press 45 pounds, you wouldn't add any weight to the bar at all.

Read more: Alternative Exercises for Bench Pressing

If you want to bench press 135 pounds, you'd add a 45-pound weight plate on each side of the bar, because the total amount you're lifting is the weight plates (45 + 45 = 90 pounds) plus the additional 45 pounds from the bar.

And finally, it's safest to always use a spotter. That doesn't mean you should run screaming to the assistance of anyone you see benching without a spotter in the gym. Just keep in mind that if you are lifting, having a spotter to lend a hand is sometimes the only way to finish that last repetition, get the bar back onto the rack safely or even get out from under the bar in the case of a failed lift. Nobody wants to be that person in the gym who gets stuck beneath a bench press bar and has to holler for help — and much less so when being crushed beneath the bar results in an injury.