So long as you’ve built up some baseline level of mind-body connection, you might have a sound idea of which muscles you’re tapping during a specific exercise. You know that, for instance, deadlifts call on the backside of your legs because they always leave your hamstrings sore. Or maybe you can feel your pecs light up as you perform a fly. 

What’s not so clear: Your core is always at work in the background, regardless of the movement. In other words, every exercise you perform is technically a core exercise—if you do it properly. 

Your core at work during exercise

You can think of your core as a cylinder that sits in your midsection, says Meghan Sak-Ocbina, DPT, ATC, CSCS, a physical therapist, certified athletic trainer, and strength and conditioning specialist. 

At the top is your diaphragm, the body’s primary breathing muscle. The front of the cylinder is the abdominals; there’s the transverse abdominis (the deep core muscle that runs across your waist like a corset), the rectus femoris (aka the “six-pack” muscles), and the external and internal obliques (which sit on the front and sides of your waist).

On the backside of the cylinder are the multifundi (tiny muscles deep in your back) and the erector spinae (which run alongside your spine). At the bottom lies the pelvic floor, which plays a crucial role in pressure management, Sak-Ocbina says. 

Noticeably, these muscles work hard during classic core movements such as planks, leg lifts, and bird dogs. But less obvious is their activation during exercises that aren’t so core-specific.

“With squats, deadlifts, and other exercises where you’re thinking about using your legs or your back, for example, the core is involved in being able to execute those movements with strength and without pain,” Sak-Ocbina explains. “From a performance standpoint, [the core] is very important as well.”

1. It supports pain-free movement

That pain-free movement benefit stems from the core’s ability to stabilize and protect your spine (plus your internal organs) and support a healthy posture.

Consider a barbell back squat. Your core is in charge of maintaining a neutral spine while the load of the bar attempts to compress it, Sak-Ocbina says. Without support from the core, the spine may be put in a compromised position. In the case of an overhead press, a relaxed core may cause more spinal extension (think: pressing your stomach forward and arching your lower back). Both of these compensations can lead to back pain and, in some cases, injury, she notes. 

“Whether you’re lying down, sitting up, jumping up, whatever it is that you’re doing, you’re collecting those core muscles to help stabilize your entire body,” says Khetanya Henderson, CPT, a certified personal trainer, 600-hour comprehensive Pilates instructor, and 200-hour yoga teacher. “So it’s being used throughout every single exercise.”

2. It enhances stability and balance

Your core lights up when you’re unstable, helping to keep you upright, says Daniel McKenna, CPT, a New York-based celebrity fitness trainer and the founder of The Irish Yank Society.

Imagine you’re carrying a baby in one arm and your groceries in another as you climb up your apartment building’s staircase. You already have to deal with two different loads on each side of your body, and the jaunt up the stairs adds an element of single-leg movement, he says. A strong, stable core prevents you from swaying to one side and topping over. 

The same idea applies when you’re on the stair climber or performing step-ups at the gym. It even factors in during single-leg exercises, like lunges, Henderson says.

“If you’re standing on one leg, you’ll be able to maintain a stronger balance for much longer if you connect to your core,” she says.

3. It transfers force and boosts its production

What’s more, the core helps coordinate movement—and, in turn, transfer force—between your upper and lower body, says Natalie Ribble, MS, CSCS, CFSC, a strength and conditioning specialist and functional strength coach at Seattle Strength & Performance. 

Think about a thruster: The power is created by your legs, your arms help float the dumbbells overhead, and your core acts like the control center for the movement. The force from your lower body travels through your core and is relayed to the other half of your body to complete the exercise, Ribble explains. Without proper core activation, you may not be able to safely do the move with as much speed or as heavy of weight.  

This performance boost from core engagement is also related to the law of irradiation—the idea that when you’re contracting a muscle hard enough, you’re also recruiting neighboring muscles, which enables you to produce even more force, Sak-Ocbina says. 

Say you’re doing a pull-up. If you squeeze your hands tight on the bar, you’re able to better activate your forearms, biceps, and lats, giving you a stronger pull. The same idea applies to the core, Sak-Ocbina says.

“If you’re pulling dead weight with a pull-up or you’re not engaging your core with a deadlift, then you’re not going to be able to generate as much force just because you’re not as stiff and stable,” she says. 

“Whether you’re lying down, sitting up, jumping up, whatever it is that you’re doing, you’re collecting those core muscles to help stabilize your entire body. So it’s being used throughout every single exercise.” —Khetanya Henderson, CPT

How much does ‘background’ core training count?

Some people get enough core training just from their compound exercises (a movement that works multiple muscle groups at once) and may not feel like they need to practice direct core exercises like planks, crunches, and Paloff presses, Sak-Ocbina says. So long as you’re lifting heavy enough, your core has to work really hard to execute those movements, she says. 

Still, by and large, it’s valuable to incorporate independent core training into your routine, according to the experts. As a physical therapist, Sak-Ocbina has found that a lot of folks don’t have a strong connection to their core, have less-than-ideal breathing mechanics, are dealing with pelvic floor dysfunction, or a combination of all three. Prioritizing core isolation exercises lays essential groundwork; it gets people familiar with the process and sensation of activating their core without the distraction of trying to contract other muscle groups. 

Many people spend the majority of their day sitting or lying down, so the core consequently spends more time in a relaxed state, especially compared to someone who does manual labor or is up and on their feet for hours at a time, Ribble says. With a more sedentary lifestyle, you may not be giving your core enough love if you’re just training it via compound movements.

“After we’ve gotten [people] to feel what it feels like to really connect with their core, then we put it back into those big movements—that’s where you really get a lot of benefit because that’s obviously where you can load the body the most but [they] also [are] the most functional, relevant-to-life type movements,” she says. 

Plus, “making sure that we do intentional core training is going to help us be stronger through all those other movements and be able to do those movements heavier and more safely,” Ribble says.

To balance the two, McKenna suggests adding a five- to 10-minute core-specific circuit on to the end of your strength-training workouts.

“In my opinion, you can do that as many times a week as you want, as long as it doesn’t take away from your other workouts,” he says.

If you’re training your core so hard that you’re not able to lift as heavy or move weight as quickly the next day, that’s a sign to ease up on the isolation exercises, he advises.

Ideally, those isolation exercises are functional, meaning they mimic how you move in your everyday life, according to the experts. Your core’s main function on a day-to-day basis is to stabilize, so choose anti-rotation, anti-lateral flexion, and anti-extension exercises such as planks, dead bugs, Paloff presses, and carries, Ribble says.

You should be training your core to move in all directions, too, adds Sak-Ocbina. Incorporate chops, side or Copenhagen plank dips, physio ball crunches, and hanging leg raises—her favorite moves to work in multiple planes of motion—into your routine. 

“Every workout is an opportunity for a core workout. You don’t necessarily have to sit down and do so many sit-ups and crunches and twists.” —Daniel McKenna, CPT

How to get the most core benefits out of your workouts

Before you do any heavy lifting, Ribble recommends practicing a couple of core-specific activation exercises to ensure all the muscles are awake, firing, and working together. Then, focus on your main movements, whether that’s squats, deadlifts, or rows. 

The amount of load and level of instability involved in the exercise will affect how much work your core has to take on. For example, a bent-over dumbbell row will be more taxing on your core than a dumbbell row performed with your knee resting on a bench. A deadlift requires more core bracing and activation than a seated hamstring curl, she explains. 

With that in mind, make sure you don’t program too many exercises that are taxing on the core back-to-back, she suggests.

“Have a balance of exercises [with] some that are going to be taxing on the core and lower back—because that’s how you build strength in those positions and in those areas—but also [make sure you’re] not overdoing it, especially for folks who are more sensitive to lower back strains or anything like that,” Ribble says.

As you move through your workout, make sure you’re properly bracing your core. For lifting, the goal is to create something like a “pressurized barrel” with your core muscles, Ribble says. Here’s how to practice:

• Kneel on the floor and place your hands on the sides of your waist at belly button height.
• Then, press your middle fingers and your thumbs into your abdomen as if you’re squeezing them together.
• Hold them in this position, and as you exhale, try to press your core muscles out into those four fingers. That’s your core engaging and creating the intra-abdominal pressure that protects the spine and allows for coordinated movement, Ribble says.
• Hold it for 10 seconds, then shake it out to feel the difference between a relaxed and braced core.

Once you’re familiar with the process, practice creating that brace and relaxing while you’re driving, on the phone, or going for a walk so it becomes second nature when you’re training, she suggests.  

When you’re a pro at bracing, a lifting belt can further enhance your core engagement during super-heavy lifts, too. There’s a misconception that belts “replace” your core, but if you’re using them properly, they act more as a palpable cue, Sak-Ocbina says.

“If you’re pushing into the belt with your stiffening muscles, the belt is going to push back toward your muscles, and you’re actually going to be creating more intra-abdominal pressure,” she explains.

If you plan to wear one, make sure you know how to brace properly without a belt first and perform a few sets of your chosen exercise before you add on the accessory, she suggests.

In Pilates, focus on the breath—imagining your lungs expanding, ribcage opening, and diaphragm dropping as you inhale and the reverse as you exhale—and pay attention to your instructor’s cues, Henderson suggests. Then, slow down your movement.

“If you slow all of the work down, you’re going to get more of what you’re looking for—more abdominal connection—and you’ll feel the muscles that are being used,” Henderson says. 

The bottom line

Your core is always working behind the scenes to protect your spine, keep you stable, and enhance performance—regardless if you’re performing BOSU split squats, Arnold presses, or single-leg deadlifts.

“Every workout is an opportunity for a core workout,” McKenna says. “You don’t necessarily have to sit down and do so many sit-ups and crunches and twists.” 

Still, it’s valuable to include a mix of compound movements and functional core-isolation exercises in your workout regimen, Ribble says. There’s a symbiotic relationship between the two types of exercises, and practicing both will only make you a better athlete and human.