You’re busy. We’re busy. We’d love to give you the perfect workout that’ll save you time and give you the most bang for your buck; so we consulted the studies from the American Council on Exercise, which has periodically studied the muscle activation of certain exercises on specific body parts. Here’s what you can learn from science—and why training your body is still something of an art.
So, I should do only these exercises, right?
First things first: “These studies are looking at which exercise in isolation causes the most activity in a particular muscle,” says Jessica Matthews, M.S., exercise science professor at Miramar College in San Diego, CA, and senior advisor for health and fitness education for the American Council on Exercise. “But that doesn’t mean they’re the best exercise.” Your goals are a better guide of what exercises are right for you; if your end-all is bigger muscles and symmetry (say, as a bodybuilder), then, yes, incorporating these into your routine makes a lot of sense. If you’re more interested in increasing your overall fitness, though, you may be better served choosing exercises that improves the body’s function—i.e., how it moves on a daily basis. “And if you’re someone who only has time to train two to three times per week, it’s essential to have a well-rounded routine to train the whole body in one workout.” That said, here are the goods, according to science.
For the front delts
With their multi-directional movement and corresponding muscles to power such movement, the shoulders can’t be properly targeted with just one move. For the most muscle activation in the front delts, ACE found the dumbbell shoulder press was best. Next up, how to hit the rear and side delts.
For the side and rear delts
The side and rear delts got their biggest workout from the 45° incline row and the seated rear lateral raise. “These (and the dumbbell shoulder press) are all great, effective exercises to incorporate into one’s fitness routine,” Matthews says. One that you may want to skip: upright rows. Not only did the research show it was least effective at targeting the delts, the movement pattern may have contributed to painful shoulder impingement. “For those seeking a safer and more effective shoulder exercise, I’d recommend a move like the shoulder press along with an exercise like shrugs to effectively strengthen the traps,” says Matthews.
For the biceps
To acutely target the biceps, ACE researchers found that the concentration curl most effective. “Having the upper arm fixed against the leg results in minimal activation of the anterior deltoid, which results in more muscle activity in the biceps brachii,” explains Matthews.
For the triceps
The triceps get quite the boost from triangle pushups, while dips and triceps kickbacks are a close second. “I would use this variation on the traditional pushup because it also strengthens the chest, shoulders, and core, giving you a great bang for your buck,” she says.
For the pecs
The pecs pump most promisingly with the barbell bench press and the pec deck. “Both of these exercises effectively target the muscles of the chest, making them great choices for those who are interested in hypertrophy—increasing muscle size,” says Matthews. At the bottom of the list, surprisingly, came the noble pushup (in all three variations tested, no less). But don’t give it up just yet. “It elicited less muscle activation in the chest because it engages a number of different muscle groups simultaneously,” she says. “This makes it a great functional exercise that can help you make the most out of your training time.”
For the lower and upper rectus abdominus
No suspense here: The traditional crunch tested highest for both lower and upper rectus abdominis activation, and hand position (behind head or across chest) makes no difference.
For the external obliques
The decline bench curl-up hit the external obliques hard. “What’s important to note is that these exercises can place higher compressive loads on the spine,” Matthews says. “For individuals with existing lower back issues, they may not be the best exercise option.” The lowest ranked exercise on the test was the side-plank for targeting the six-pack and V muscles. But vanity isn’t (or shouldn’t be) everything in core training. “It’s important to also include other exercises that effectively target the core’s deep musculature to enhance spinal stability, which is important for movement and everyday life, and can help to lower the risk of developing back issues later down the road,” says Matthews. The side-plank, among other exercises, does just that.
For the glute max
If you want to target the mighty glute max, quadruped hip extensions (and their weight-loaded cousin, pendulum quadruped hip extensions) will give you the most mass.
For the glute medius
Squats and step-ups seriously strengthen the glute medius muscle, and these exercises train two of the five primary movement patterns (hip hinge and single-leg, respectively) to boot. Less beneficial from a glute-activation standpoint: legs presses (both vertical and horizontal.) "Due to the positioning of the body, the hips are not able to move into full extension at the top of the movement,” Matthews says. So while other muscles of the legs are challenged, the glute is left out. If your aim is to train functionally (i.e., getting the muscles to work together), Matthews suggests any type of loaded squat. “It trains a primary movement pattern, while focusing on joint stability and mobility along with core integration, and utilizes external load to promote hypertrophy.” So yeah, keep on squatting.