You've probably heard a fitness instructor tell you to "engage your core" during class. That's because your core initiates and stabilizes pretty much all your movements. Plus, having a strong core improves your balance (according to a March 2019 study in PLOS One) and can help prevent injury.
But let's back up a bit. What is your core, exactly? And how might you know if you have enough core strength? Plus, do you really need a strong core to get those highly coveted six-pack abs? Here's what experts have to say about core workouts and core strength.
What Muscles Make Up Your Core?
Your core isn't just your six-pack muscles. "It's layers of deep muscles that help support your pelvis, spine, butt, back, hips and stomach," says Katie Dunlop, CPT. "They are the foundational muscles for keeping our posture strong and tall and allowing us to twist, bend, run, jump and just move."
There are several main core muscles. These include:
- Rectus abdominis (the six-pack muscles)
- Transverse abdominis (the lower abs or the "seatbelt")
- Inner and outer obliques (they're on your sides and help you twist side to side)
- Multifidus (the deep muscles of your lower back)
- Erector spinae (the muscles that run along your spine)
- Diaphragm (the muscle at the bottom of your ribcage that supports breathing)
- Pelvic floor muscles (the muscles low in your pelvis that help control continence and have a huge role in pregnancy and birth)
"It also involves muscles of your back, chest and glutes," says Kat Wiersum, certified Pilates instructor at Amplified Pilates Center and interval instructor at Studio Three in Chicago.
How Do You Know if Your Core Is Weak?
When you have insufficient core strength, you can feel the ripple effects in just about every movement. According to Dunlop, some signs to look out for include:
- Poor posture or pain when trying to correct it
- Back pain you can't pin to an activity (like muscle soreness or injury)
- Poor balance
- Back pain after standing for a long time
What's more, if your back or neck is the only thing that's sore or worked after a core workout, you probably aren't using your core to support the movement you're doing, Wiersum says. That can be a sign of a weak core.
"Another way is to check when you're doing a push-up or a plank. Does it look like your belly button is pushing outwards? If so, try and engage to bring it towards your spine," she says. If you feel that outward push and you can't pull it in, your core is on the weaker side.
And while there are a few ways you can test your core strength, doing a bunch of crunches isn't one of them. Instead, Wiersum recommends this core exercise:
- Lie on your back, arms up toward the ceiling to start.
- Bring your hands down toward the floor like you're trying to reach for your feet.
- At the same time, lift your head, neck and shoulders up, trying to lift to about the tips of your shoulder blades.
If you can do this and can feel your belly button pulling down toward the floor without creating tension in your neck, then your core is probably pretty strong. (Kudos!)
Read more: What Are the Signs That Your Core Muscles Are Weak?
What Are the Best Core Exercises?
One of the great things about building your core strength is that you can incorporate it into any exercise by activating the muscles in your abdomen as you move through it. The more engaged and active those muscles are, the stronger they become.
You can also incorporate core-strengthening exercises into your workouts. "Great core exercises include toe taps, dead bugs and plank variations," says Wiersum. And science confirms that planks are one of the best core-strengthening exercises you can do, per a March 2016 study in Physical Therapy Rehabilitation Science.
"They are a full-body movement," Wiersum says. "Planks force your ab muscles to fight against gravity to stay engaged and pulled in which helps teach your body to appear 'flattened' on your stomach."
Move 1: Toe Taps
- Lie on your back, legs at a 90-degree angle and knees over your hips.
- Then, one leg at a time (or with both legs), hinge your knees so your toes move toward the ground. Only go as far as you can while maintaining a tiny space under your lower back (a neutral pelvis position).
- Then, with an exhale, lift your legs back up to their starting position, using just the strength of your abs.
"Think of your legs being dead weight, keeping the true 90-degree shape, and not worrying about the distance down; it's more about working the way up," Wiersum says. "It should feel like there is a seatbelt tightening from one of your hipbones to the other."
Move 2: Dead Bug
- Start lying on your back, legs at 90-degree angles and knees over hips. Arms are extended straight up toward the celling.
- Reach one arm overhead toward the floor as you extend the opposite leg straight out away from you.
- Exhale and think about pulling your belly button down to the floor to bring your leg and arm back to the start position.
- Switch sides.
Move 3: Forearm Plank
- Lie on your stomach and prop yourself up on your forearms, parallel to each other.
- Lift your body off the floor so that only your forearms and feet are in contact with the floor. Your shoulders should line up over your elbows.
- Your body should be in a straight line from shoulders to heels, as your belly button pulls up to your spine.
- Remember to keep breathing while holding the position.
- Start with holding 10 seconds, then try 20, 30 or 60.
Think of it as "lacing up your abs," like you're trying to tie up a corset around them. "Think about actively pushing into the ground, activating your quads and glutes, and try to reach your heels back away from your head," Wiersum says.
Planks on your forearms are a bit more challenging for your abs, as you're in more of a straight line, but balancing on your hands is a little more challenging for your arms and wrists.
Can You Have a Strong Core but Not Abs?
Yes and no. "You can have a strong core but not have visible abs," Wiersum says. "Everyone has a different body composition naturally, and some of the strongest people will never have a huge amount of muscle definition."
It depends heavily on your body fat percentage. The higher it is, the lower the chances you'll have visible abs, even if you have Superman's core strength.
But on the flip side, having visible abs doesn't necessarily mean you have a strong core, she says. "Usually a defined six-pack does mean you have strong rectus abdominis muscles, but the rest of the muscles of the core can easily be neglected for the so-called 'vanity muscles,'" says Wiersum.
For a well-rounded and functional core workout, pay attention to as much of the muscles in your trunk as possible. Six-pack abs may come and go, but a strong midsection will serve you well your entire life.