You’ve probably heard the phrase “engage your core” at least once in your life, even if you’ve never seen an exercise program, read a fitness magazine, or set foot in a gym. Sometimes it’s gently encouraged, while at other times it’s yelled while you’re sweating out your last rep.

However, you may wonder what your core is, what it means to engage it, and how to do so.

Your core consists of the muscles surrounding your trunk, including your abdominals, obliques, diaphragm, pelvic floor, trunk extensors, and hip flexors.

Your core provides stability to your trunk for balance and for movements like lifting weights and standing up from a chair. It also provides mobility to allow your torso to move as needed, such as when you reach for your seatbelt or swing a golf club (1, 2, 3).

Furthermore, your core muscles are involved in everyday activities such as breathing, posture control, urination, and defecation (4).

Every time you exhale and inhale, your diaphragm plays a large part in allowing air to flow into and out of your lungs. When you sit up straight, your core muscles contract to keep your trunk upright. When you use the bathroom, they’re there to start and stop your business.

This article discusses what the core muscles are, describes their role in trunk mobility and stability, and reviews core exercises that you can incorporate into your workout regimen.

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Several muscle groups make up your core muscles.

Rectus abdominis

The rectus abdominis, also known as the six-pack muscle, attaches from your lower ribs to the front of your pelvis. The primary movement it performs is flexing your spine, such as when you sit up in bed or perform a crunch.

This muscle is the most superficial of all the core muscles and is therefore not as useful for spinal stability (5).

Internal and external obliques

The internal and external obliques attach on the lateral sides of the trunk from your ribs to your pelvis. Statically, they provide stability to the front and sides of the trunk.

Their primary movements involve trunk rotation, such as when you swing a baseball bat, and side bending. When they work bilaterally, they also flex the spine.

Transversus abdominis

The transversus abdominis originates from many points, including the back and top of the pelvis and the lower six ribs. Its fibers run horizontally around the body to the linea alba, or midline. It’s the deepest abdominal muscle, and its job is to provide support to the spine.

When the transversus abdominis is engaged, it co-contracts with the multifidus muscle to provide deep, segmental stability to the lower back in particular (6).

People with chronic low back pain often benefit from strengthening these muscles.

Pelvic floor

The pelvic floor muscles are located on the underside of the pelvis and act similarly to a hammock or sling. When engaged, they lift upward toward the stomach.

These muscles start and stop the flow of urine and feces but also act as deep stabilizers of the spine and pelvis (7, 8).


The diaphragm attaches to the underside of your lower ribs.

It’s the primary muscle responsible for breathing in and out, but recent research suggests it also plays an important role in cardiac function, lymphatic return, regulating emotional states, swallowing and vomiting, lumbar stabilization, and pain tolerance (9).

Back extensors

Your back extensors are multilayered muscles that include the erector spinae muscles, quadratus lumborum, and multifidus. In general, they attach the spine to the pelvis or an individual vertebra to the vertebrae above and below.

Their primary functions are spinal extension (bending backward), postural support, and supporting the spine when you’re bending forward and lifting loads, such as during squats or biceps curls.


The iliacus and psoas major are two hip flexors that converge into one muscle belly, which is why they’re often called the iliopsoas. They originate from the thoracic and lumbar spine (psoas) and the iliac crest of the pelvis (ilacus) and insert on the femur, or upper leg bone (10).

The iliopsoas flexes the hip, or brings your legs toward your torso, such as when you do high knee exercises. But because it is also connected to the spine, it’s considered a deep core stabilizer (10).


Your core is made up of several muscle groups, including your abdominals, pelvic floor, diaphragm, back extensors, and some hip flexors.

Engaging your core muscles can mean many things, depending on what you’re trying to achieve. For instance, if you’re doing situps, the muscles recruited and the order in which they fire will be different than if you’re trying to hold your balance while standing on one leg.

What’s more, the way your muscles feel when you engage them will differ depending on several factors, such as whether you’re trying to move your spine or stabilize it, whether you’re pushing or pulling weight, and whether you’re standing, sitting, or lying down.

Regardless of how, when, or why you engage your core, it’s important to realize that in movement these muscles all function in harmony with each other. They don’t work in isolation.

For a truly strong and functional core, it’s important to be able to engage your core in any situation and in every way, providing dynamic stability and spinal support for your moving body. For the purposes of this article, we will discuss four primary ways to engage your core.

Concentric contraction of the abs or back

If you’re doing a traditional ab exercise like a crunch or a back exercise like the superman, you are using core muscles as prime movers.

In the crunch, for example, the rectus abdominis and obliques contract concentrically (in other words, they shorten) to pull your ribs toward your hips, lifting your shoulders and head.

Concentric contractions are used to generate movement or accelerate the body (11).

These are the most familiar types of muscle contractions for many people.

Eccentric contraction of the abs or back

Eccentric contractions are used to decelerate the force or movement of the body. They are lengthening contractions and always happen in tandem with a concentric contraction on the other side of the joint.

For instance, if you’re sitting at your desk and notice that you’re slumping, two contractions will happen when you straighten and lift your spine: concentric contractions in the spinal extensors and an eccentric, or lengthening, contraction in the abdominals.

Both are important for core function.

Abdominal bracing

Abdominal bracing is an isometric contraction of the muscles of your abdominal wall that does not move or change the position of your spine, ribs, or pelvis (12).

It is used as a way to protect the spine when moving heavy loads, such as when lifting weights.

Research has shown that abdominal bracing is superior for activating the superficial abdominal muscles (13).

Abdominal draw-in or hollowing

The abdominal draw-in maneuver, also known as abdominal hollowing, happens when you focus on bringing your navel to your spine. This type of contraction is used for stability, such as bracing, and is most effective when thought of as a dynamic part of your exhalation.

Research has shown that drawing the abs in, or hollowing them, is more effective for engaging the deep spinal stabilizers and transversus abdominis than bracing is (13).

While there are very vocal proponents of both types of stabilization contractions, the most functional core is one that can perform both the bracing and hollowing techniques effectively and uses each method when required.

Below are basic abdominal stability exercises you can use to engage your core. They’re by no means exhaustive but are helpful in understanding how to engage your core muscles.

The abdominal draw

  1. Lie on your back with your knees bent. (You can also do this while sitting up straight.) Inhale.
  2. Exhale to pull your stomach in, imagining bringing your belly button to your spine. You should still be able to breathe but may feel the muscles around your abdomen and sides tighten. Your back shouldn’t move — make sure it isn’t arched or pushed into the floor.
  3. Hold for 5–10 seconds. Relax. Repeat.

The plank

  1. Start in a pushup position on your hands and toes. If this is too difficult, you can lower to your knees.
  2. Draw your abdomen toward your spine and keep your buttocks in line with your body. You should feel all the muscles in your abdomen working.
  3. Hold this position for 20–60 seconds.

It’s important to note that this exercise puts high loads on your spine. If you experience back pain, it’s a good idea to refrain from this exercise or to modify it by doing a wall plank or plank on your knees.

The side plank

  1. Lie on your side with your elbow on the floor and one foot on top of the other. Your upper body will be propped up. Reach your top arm to the sky or keep the hand on the floor for added balance.
  2. Lift your hips into the air and straighten your legs so that you’re supporting yourself on your forearm and the side of your foot. If this is too challenging, keep your knees on the floor and make a straight line from knee to head.
  3. Maintain good alignment of your feet, hips, and elbow. Also, keep your shoulder over your elbow. You should feel the obliques on your bottom side working.
  4. Hold this position for 20–60 seconds.

The bird dog

  1. Start on your hands and knees, as if you’re a table. Maintain a neutral spine.
  2. Reach one arm out in front of you so it’s even with your head and torso.
  3. Extend the opposite leg behind you, in line with your torso and arm. Make sure to keep your hips facing down toward the floor, rather than turned out toward the side. You should feel the muscles in your abdomen and back working.
  4. Hold for 5 seconds, then repeat with the opposite arm and leg.

The dead bug

  1. Lie on your back with your knees bent and feet flat.
  2. Tighten your abdominals and keep your back flat as you lift your knees so your hips and knees are bent at a 90-degree angle.
  3. Slowly tap one toe to the floor and return.
  4. To increase the difficulty level, extend your arms straight up over your shoulders. As you lower one foot down to the floor, reach the opposite arm back overhead, keeping your lower back on the floor and your ribs pulled in.
  5. Extend your leg only as far as you can while keeping your back flat.
  6. Return and switch sides.

The bridge

  1. Lie on your back with your knees bent and your feet hip-distance apart.
  2. Keep your trunk and pelvis together as you squeeze your buttocks and lift them off the floor.
  3. Hold for a count of five.
  4. Relax and return your trunk to the floor. Repeat.

There are many exercises to engage your core muscles. Basic ones include the abdominal draw, plank, bird dog, dead bug, and bridge.

Your core has multiple functions, including stabilization, balance, breathing, and bowel and bladder control.

Spinal mobility

While we often think of the core muscles as important stabilizers (because they are!), they’re also the muscles responsible for mobilizing your spine through flexion, extension, lateral flexion, and rotation.

Trunk stability

During activities such as lifting something over your head, picking something up from the floor, and pushing or pulling an object, your core muscles contract to keep your trunk stable and support your spine (14).

These muscles are also important in weightlifting and athletic pursuits such as judo, running, and soccer. Keeping your spine stable reduces the risk of injury (12).


Your core muscles aid in maintaining balance when you’re standing still, as well as when your balance is challenged dynamically (14, 15).

For example, when someone bumps into you, your brain and trunk recognize this abrupt force and change in balance. Your core muscles then react to help keep your body upright.

Your core muscles also support balance in activities like Olympic weightlifting, in which your trunk has to react and stay stable during changes in weight distribution.

Breathing and trunk stability

Your diaphragm is a major muscle in control of breathing. It has an inverted “U” shape and lines your lower ribs.

It flattens as it contracts, allowing room for your lungs to expand when taking in a breath. Conversely, when your diaphragm relaxes, it compresses your lung cavity, forcing air out of your lungs similarly to the way bagpipes work.

In addition, your diaphragm can isometrically contract to hold your breath when you’re straining to lift something heavy. This action supports your trunk to avoid injury and maintain stability (2).

Bowel and bladder control

Your pelvic floor muscles help control your bowel and bladder, allowing you to urinate or defecate (or to hold it if you can’t make it to the bathroom).

If these muscles aren’t strong, a condition called incontinence occurs. However, in many cases, these muscles can be strengthened to help prevent or manage this condition.

Additionally, the pelvic floor and diaphragm muscles work in conjunction with the rest of your core to maintain spinal stability by increasing abdominal pressure at your spine (16).


The core muscles have multiple functions, including trunk stability, balance, breathing, and bowel and bladder control.

You engage your core during a variety of basic scenarios, such as:

  • Sitting. Sit up tall with your back straight but not arched. Draw your belly button toward your spine. You can also tighten your stomach as if someone were about to punch you in the gut.
  • Breathing. Relax your abs, shoulders, and neck. Slowly breathe in, letting your stomach gently push outward. Try to minimize the amount your shoulders rise (or shrug) toward your ears, as this means you’re using accessory shoulder and neck muscles to breathe.
  • Weightlifting. Your core engages during resistance activities in which you’re holding weight in your arms, such as biceps curls, squats, deadlifts, and military presses. You can also engage one side more than the other by doing single-arm or single-leg exercises.
    • One study of various exercises found the highest rate of voluntary core contraction with free weight exercises (17).
  • Cardio. Cardiovascular activities involve multiple movements in varying directions, therefore engaging the core.
  • Yoga. This popular practice involves the core in many movements, including planks, bridges, and side planks, as well as in balancing on one or both feet for positions like Tree Pose and Warrior Pose, among others.
  • Pilates. Practicing Pilates is effective at strengthening the core both in mobility and stability exercises. With a focus on deep spinal support, Pilates — when taught effectively — is ideal for learning to engage your deep core muscles.

You can engage your core while sitting or breathing. You also use your core extensively during weightlifting, cardio, and yoga.

Engaging your core means contracting your trunk muscles to provide support for your spine and pelvis in static positions and during dynamic movements. These muscles are used for balance, lifting, pushing, pulling, and general movement.

A strong core helps improve balance, decrease the risk of injury, and support your spine during forceful movements.

Put simply, your core muscles are involved in the stability and mobility of your spine. They’re the “core” of all the movements your body does throughout the day. Learning to engage these muscles effectively will help you move pain-free for years to come.