Do you struggle with any type of inversion, on the ground or in the air? Do your backbends feel unstable or alway end up too much in your low back? Does your belly “pooch” whenever you sit up? Do you suffer from low back pain? When one of my students complains of any of these issues, the first thing I check is generally their core engagement, and more specifically, their deep core activation.
Before getting into any details, I want to mention that I am only a fitness coach and an athlete. I am not a doctor or physio. While I did not study kinesiology or any related field in college, I do have years of experience coaching students, identifying movement problems, and creating exercises to address these issues. In the following sections, I will be referencing experts and will include some useful readings by these specialists if you’d like to learn more.
One more thing. People often confuse core strength with six-pack abs. This blog is not about how to get six-pack abs. While deep core strengthening can have a flattening effect on the belly, that is not the main intention of the exercises that will be shared here. Also, all bodies are different, and while everyone can strengthen their core, not everyone can safely get six-pack abs. Getting “ripped” is often more about diet and cardio exercise than strength training, and that’s all I’m going to say about that.
What’s the point of core strength?
Strengthening the core muscles has two main purposes: (1) increasing torso curling ability in the front, side, and back directions and (2) improving stability. In terms of torso curling, we can shorten the distance from our hips to our shoulders by using our front core (like the position of the body while performing a crunch, referred to as spinal flexion), side core (think side bending, also known as lateral flexion), or back core (as in back bending, which is referred to as spinal extension). The term C curve refers to the rounded spine position where we use our front core to shorten the space from our pelvis to our shoulders. All three of these positions that require core strength are used in aerial and pole movements, however, students usually come across the C curve in spinal flexion first, and side and back bending on apparatus are usually introduced a bit later.
Core stability is important not only for aerial and pole, but also just for daily movements such as walking. Core stability refers to one’s ability to resist front, side, and back bending and rotation of the torso against external forces. For example, when static spinning on pole, one of the forces acting on the body is pushing the torso outwards from the pole, and core stability works to maintain the desired torso shape (which will depend on the type of spin and what shape you’re spinning into). When performing a standard straddle invert, we must use our front core to fight the force of gravity and prevent our spine from going into a back bend shape. Core stability is essential for injury prevention. If a student is struggling to achieve a certain movement, one of the most common issues is a lack of core stability. If the core is not stable, the body will feel heavy and will be difficult to control.
Muscles in the core
Muscles are often classified as stabilizers or movers. A stabilizer muscle works to maintain a joint, limb, or body position and resists external forces. A mover muscle is used to move the body into a particular position. The stabilizer muscles assist the primary movers by helping to prevent overuse of the movers as well as maximizing efficiency of the movers.
The main stabilizer muscles in the core are the transverse abdominis (located in the front core), the internal obliques (located in the sides), the multifidus (along the lumbar spine), the diaphragm (a corset-like muscle around the abdomen) and the pelvic floor muscles. The iliopsoas are also considered core stabilizers, as they attach the lumbar region of the spine (in the low back) to the pelvis. There are other muscles that are also used in core stability, but these are the main ones that we’ll be discussing here.
The primary movers of the core depend on the direction of the torso curl. To bring the body into a front C curve, the main mover muscle is the rectus abdominis (commonly referred to as the six-pack muscle). For side bending, the external obliques and quadratus lumborum must be used. The obliques are also used to rotate the torso. Back bending requires the erector spinae (sometimes referred to as paraspinals) and the latissimus dorsi to engage. Again, other muscles are involved but we will focus on these muscles here.
Types of muscle engagement
There are three categories of muscle engagement, concentric, eccentric, and isometric. The type of muscle engagement depends on the length of the muscle that is being engaged relative to its length at rest. Most people are familiar with concentric engagement. A muscle is concentrically engaged if it is shortening under tension. For example, the rectus abdominis engages concentrically during a sit-up. A muscle is eccentrically engaged if it is lengthening under tension. During backbending, the abdominal muscles are being stretched, but they must also be eccentrically engaged. A muscle is isometrically contracted if it is maintaining its length while being engaged. This type of engagement is used to resist movement, and if a muscle is being contracted isometrically, then it is in a stabilizer role. Many exercises require the main mover muscles used to contract in all three of these ways, each at a different phase of the exercise.
Muscular co-contraction refers to when muscles on opposite sides of a joint contract. If a muscle engages concentrically on one side, the opposing muscle will engage eccentrically at the same time. For example, in a bicep curl, the bicep engages concentrically but the tricep also engages eccentrically. Co-contraction is important for joint stability.
Common causes of core dysfunction and instability
There are many reasons why the core might not engage the way that it should in a particular movement. Sometimes there is a muscular weakness, but often other issues are involved. If you spend most of your day sitting, your core may be weak since it does not need to engage to stabilize the torso as much as when you are standing or performing an exercise.
Overactive hip flexors can also be a sign of core weakness or dysfunction. If the transverse abdominis, pelvic floor, and diaphragm are not engaging properly or are weak, the hip flexors may take over and act as core stabilizers. This can cause issues such as tight hip flexors and low back pain.
Another common issue I’ve seen in my students is diastasis recti. This is a condition where the rectus abdominis has been separated (into left and right parts) and is common after pregnancy. Note that if you have diastasis recti, you should consult your physician before trying out any of the exercises in this blog. Many of the standard exercises used to strengthen the core can make diastasis recti worse (including planks, sit-ups, and even the yoga pose downward dog), so it is important to check in with your doctor.
Poor posture can contribute to core dysfunction. Every body is different, so there’s not just one posture that is perfect for everyone. In general, the ideal posture aligns joints vertically. In terms of standing, this means that there is a straight line from the ears, to the shoulders, to the hips, and finally the ankles. This same principle of stacking joints is used in acrobatics and aerial arts to position the body in the most efficient position for muscular endurance and stability. However, the most important thing is that the body is not always in the same position. Your body must be in different positions throughout the day to avoid over-using some muscles and over-stretching others. For example, somebody who is always in a slouched position will have over-stretched lats (latissimus dorsi).
Breathing issues can always cause core problems. Ideally, diaphragmatic breathing should be used. The diaphragm and pelvic floor are some of the main muscles required for breathing. The diaphragm allows for inhalation as it opens the ribs so that the lungs can expand. When breathing is functioning well, the diaphragm and pelvic floor move together in an up and down motion. Note that the rectus abdominis, obliques, and transverse abdominis are all used during the expiration phase of breathing. If someone is having core stability issues, it’s important to also check in with their breathing. In general, breath should not be held, as this can cause an internal pressure issue which can affect the core. Rib compression can negatively impact the pelvic floor-diaphragm movement. For example, over-training the expiration muscles can impede the diaphragm's ability to open the ribs, which is essential for the inspiration phase of breathing. If the ribs can't open enough, then the diaphgram and pelvic floor action can get thrown off. We will discuss proper breathing as it relates to the exercises that will be presented in a later section. In general, for exercises that bring the spine into flexion (like a sit-up), the breath should be exhaled during the sitting up phase of the exercise and inhalation should occur during the lowering down phase (when the rectus abdominis is contracted eccentrically).
Exercise intention & goals
Have you ever felt confused about an exercise when two instructors taught it to you differently? I have! Instructors may teach exercises differently depending on their intention for the exercise. Most of the exercises that I will present here can be safely and productively performed in different positions and with a focus on various muscles. The way we position our bodies and the muscles that we choose to pay the most attention to will depend on what we hope to achieve with the exercise. I will try to clearly state my goals and intentions for each exercise, and I encourage you to always think about this when you work out as well. For example, if I’m warming up my front core for backbending, I may choose to have my spine in its natural position with a slight curve in the lumbar region of my spine. However, if I’m doing front core exercises to strengthen my spinal flexion, then I will generally keep my pelvis posteriorly tilted, eliminating the natural, slight, low back curve.
What does deep core activation feel like?
Many of us struggle to know when our core is engaged and which muscles are being used. It is important to develop an awareness of the core in order to do exercises correctly. Here is a list of common cues used to activate the deep core (core stabilizer) muscles, such as the transverse abdominis and the pelvic floor:
Pretend you’re trying to stop the flow of urine (pelvic floor)
Suck your pelvic floor upwards (pelvic floor and diaphragm)
Suck your belly in towards your spine (transverse abdominis)
Bring your sit bones towards each other (pelvic floor)
Cough (transverse abdominis, pelvic floor, diaphragm)
Not all of these cues may work for you. Make sure that you don’t end up holding your breath to try to satisfy these directions - your pelvic floor and diaphragm should be able to continue moving up and down throughout most exercises. If your belly pooches out while doing a spinal flexion exercise, you may be under-utilizing your transverse abdominis or over-using your rectus abdominis. In general, if someone is engaging their abs but their belly is sticking out a bit, then the exercise is likely mainly working the rectus abdominis. Another thing to keep an eye on is leg and foot position - make sure both feet and knees are facing forward, and not turning outwards. For the exercises presented in this blog, we will try to shift our focus to the deeper core muscles. The transverse abdominis will have more of a flattening or corset-like effect on the belly when it is engaged.
If you’re struggling to feel and activate your deep core, you can try to squeeze something such as a yoga block between your thighs while you perform most core exercises. This squeezing action will bring your sit bones together and help you to engage your pelvic floor. If you still can’t feel your pelvic floor, you might benefit from consulting a specialist in case your pelvic floor is not functioning properly.
Core stability in pole and aerial
When performing pole or aerial tricks, many forces are working to bend or rotate the torso in different directions. For this reason, the core stabilizers must be working the entire time. Now, this does not mean you should hold your breath and contract everything as hard as possible for an entire sequence of moves. Don’t forget that you still need to breathe normally, and your pelvic floor and diaphragm must work together while engaging and relaxing to allow this to happen.
During the lifting phase of any trick, exhaling will help your front core engage. For straddle inverts, ayesha deadlifts, and shoulder mounts, for example, the spine should be flexed in a C-curve shape. To safely maintain this position, the deep core muscles must be engaged and the pelvis should be tucked (posteriorly tilted). To maintain the posterior tilt of the pelvis, the rectus abdominis and obliques must engage concentrically.
If you’re struggling with any pole or aerial move, think about which direction the forces are pushing you. For example, in a straddle invert, gravity is working to push the hips and legs back down. To prevent gravity from winning, our core must stabilize to prevent spinal extension. To give another example, in order to hold an iron-x or flag shape, we must prevent our torso from going into lateral flexion. Once you determine the main core stabilizers and movers for the trick that you are working on, you can choose appropriate off-pole core exercises to strengthen those muscles and help you achieve your goal.
Core stability in backbending
The core is also essential for a strong backbend. The deep core muscles should be engaged in a backbend to support the spine. The front core muscles will be eccentrically contracted, while the back core muscles must engage concentrically. Because the core muscles must be strong in their lengthened position, it is important to incorporate some core exercises that strengthen the ab muscles in this lengthened position as part of a backbending warm-up routine. The pelvis will be tilted anteriorly, however, the rectus abdominis should engage as if trying to pull the pelvis into posterior tilt. The glute muscles can also act as core stabilizers, and they must engage to prevent pinching in the low back. The glute max is particularly important in backbending, and it works to keep the hips in extension and the legs in slight internal rotation which helps maintain the pelvic tilt. Any low back discomfort during or after backbending is possibly due to a core issue or insufficient glute engagement.
Exercises
Here are some of my favorite core exercises. In general, the slower you can go, the better. If you have any injuries, make sure to consult your physician before trying these.
Plank
My Intention
In terms of core, I use the plank exercise to strengthen my core stability. In particular, when done correctly, it builds core strength to prevent spinal extension. It’s also a great way to build shoulder strength.
What to look for
The shoulder blades should be protracted (spread wide across the back)
The torso should be sucking in, as if wearing an invisible corset, which indicates that the deep core is properly engaged
The spine should be in a neutral position. Watch out for low back arch (anterior tilt of the pelvis) and for an overly tucked pelvis (posterior tilt). A slight posterior tuck is ok, but not a full tuck.
Squeeze your glutes to maintain hip extension.
Keep ribs in.
Core Muscles
The core muscles should all be engaged isometrically.
Variations
Planks can be done on forearms or hands. If someone has a wrist injury, they should use the forearm variation. I also like to use my forearms to build my elbow pushing strength, which is used in forearm bracket grip on pole.
Planks can be done on knees. If someone cannot maintain proper spinal position and core engagement, then they should start on their knees.
Lifting one limb off the ground. This is a great way to increase anti-rotational stability of the core.
Side Plank
My Intention
Side plank is great for increasing core stability against lateral flexion. It’s also great for shoulder strength.
What to look for
The shoulder blades should be protracted (spread wide across the back)
The torso should be sucking in, as if wearing an invisible corset, which indicates that the deep core is properly engaged
The spine should be in a neutral position. Watch out for low back arch (anterior tilt of the pelvis) and for an overly tucked pelvis (posterior tilt). A slight posterior tuck is ok, but not a full tuck.
Make sure there is a straight line from your hand or elbow on the ground (depending on the variation you’re doing), to your hips, and to your feet.
Keep ribs in.
Squeeze your glutes to maintain hip extension.
Core Muscles
The core muscles should all be engaged isometrically. The internal obliques will be working especially hard.
Variations
Planks can be done on forearms or hands. If someone has a wrist injury, they should use the forearm variation. I also like to use my forearms to build my elbow pushing strength, which is used in forearm bracket grip on pole.
Planks can be done on knees. If someone cannot maintain proper spinal position and core engagement, then they should start on their knees.
Lift your top leg up using your adductors to increase the difficulty for the core stabilizers
Add a torso rotation to incorporate oblique strengthening.
Dead Bugs
My Intention
Dead bugs build core stability. If I’m having a student do dead bugs to strengthen their core for pole or aerial, I will have them keep their pelvis posteriorly tilted. If a student is warming up for backbending, the spine should be in a neutral position, with a small space between their low back and the floor.
What to look for
Note whether there is a space under the low back or not. Make sure this is consistent with the pelvic position that aligns with your intention for this exercise.
The space between the low back and the floor should not change at any point during this exercise, especially if the legs are moved as in some of the optional variations
Tension in the upper back or neck. Keep your head resting on the ground and try not to use the upper back or neck muscles in place of the deep core muscles.
Keep legs hip width apart.
Keep shins parallel to the floor.
Keep knees over hips. Make sure knees don’t drift closer to your head, this makes the exercise much easier.
Keep ribs in.
If performing a variation where legs are lowered, exhale each time you lower a leg.
Core Muscles
The core muscles should all be engaged isometrically.
Variations
The dead bug can be progressed to hollow body holds. Use the following progressions:
Keeping knees bent at 90 degrees, tap one foot at a time on the ground
Straighten one leg at a time
Straighten both legs
Bring shoulders into full flexion (the angle at the armpit is 180 degrees and arms are reaching overhead)
Push hands on knees to start. This will force your hip flexors to activate. Extend one arm and one leg at a time, then bring them back together and repeat on the other side. Continue for as long as you can maintain the proper position, up to a couple minutes.
Put a miniband around both feet making sure to keep feet flexed. Extend one leg at a time, activating your hip flexors. Another option is to also curl the head and chest up to add rectus abdominis concentric engagement.
Hip Bridge
My Intention
Hip bridges can be used to address a variety of issues, such as glute weakness, tight hip flexors, and core stability.
What to look for
The pelvis should be tucked and glutes squeezed.
Feet and knees should be hip width apart. Make sure your knees don't go outwards as you lift your hips.
Spine should be rounded and in flexion.
Keep your neck and upper back relaxed to avoid neck tension.
If lifting a leg to perform a variation, exhale while lifting.
Core Muscles
The front core muscles should all be engaged concentrically. Back core stabilizers will engage eccentrically.
Variations
Squeeze a yoga block between thighs to assist pelvic floor engagement
Lift one leg at a time to work rotational stability.
Roll Up
My Intention
I use roll ups to strengthen the core stabilizers and increase spinal flexion strength. I slightly tuck my pelvis to train for pole and aerial inversions.
What to look for
The spine will be slightly rounded, but do not over-tuck the pelvis. If you struggle to finish the lift up or if your feet come off the ground, your pelvis may be over-tucked.
If your neck or upper back feels discomfort or tires, you may be over-rounding your upper spine.
Exhale during the lifting phase.
Core Muscles
The front core muscles should all be engaged concentrically.
Variations
To build up to this movement, try holding onto your thighs as you lower down.
Another modification is to hold on to a stretchy band placed around feet.
Hollow Body Roll
My Intention
Hollow body rolls increase core stability and strengthen the C-curve in spinal flexion, extension, and lateral flexion.
What to look for
The hips should be in extension the entire time. This is achieved by engaging the glutes. Make sure the angle at the hip joint is never less than 180 degrees (if hip flexors are tight, then maintain the largest angle you can)
Arms and legs should be straight
Legs should squeeze together
When in the hollowbody phase, shoulder blades should be protracted
When in the arched phased, shoulder blades should be retracted
Shoulders should be externally rotated. Look for wrapping of the armpits.
Core Muscles
The core stabilizers and glutes should be engaged the entire time. During the hollow body phase, the rectus abdominis is working concentrically to maintain the posterior tilt of the pelvis, and the back muscles engage eccentrically. During the arched phase, the back muscles engage concentrically while the front core contracts eccentrically. During the lateral flexion phase, the obliques engage concentrically and eccentrically (depending on which side is in lateral flexion).
Variations
If you’re building up to this movement, work all four C-curves on their on first - hollowbody, arched body, left C-curve, and right C-curve
Squeeze a yoga block between your legs to increase pelvic floor engagement and squeeze a block between your hands if you’re struggling to maintain external rotation in your shoulders
V-Sits
My Intention
V-sits are one of my favorite exercises to strengthen the core for straddle inversions and for handstand press. They improve core strength in an open chain position (feet not on the ground), which is essential for pole and aerial. I usually perform these in a slight tuck to train for inversions.
What to look for
Begin in a hollow body position except with hands reaching forward instead of overhead.
The spine will be in a neutral position. Do not over-tuck your pelvis. If you find yourself rolling back, you likely have tucked your pelvis.
If your neck or upper back feels discomfort or tires, you may be over-rounding your upper spine.
Keep legs squeezed together.
Exhale during the lifting phase.
Core Muscles
The front core muscles should all be engaged isometrically.
Variations
Bend legs
Keep legs together during the lifting phase, and then straddle legs apart and brings arms between legs
Put a miniband around thighs and separate legs, pushing into the band, if you struggle with hip impingement.
(Advanced) After lifting up into the V-shape, place hands flat on the floor next to hips, and push into the ground to lift hips up. The goal is to maintain the V-shape while lifting - I still struggle with this part!
Back Extension
My Intention
This exercise is a great way to warm up for backbending as well as just increasing back body C-curve strength. Sometimes I use this exclusively for my mid and upper back, in which case I keep my legs heavy and on the ground. If I also want to strengthen my lower back, then I lift my legs. I keep my shoulder blades protracted when I'm training for pole or aerial, and I sometimes retract my shoulder blades when warming up for backbending.
What to look for
If warming up for backbending, keep the neck in a neutral position, and look at the floor. Lift legs only an inch or two off the ground to engage the low back instead of letting the glutes and hamstrings take over. Keep glutes and hamstrings relaxed.
If strengthening the entire back body, lift legs, arms, and head high, but keep your gaze down or slightly forward to avoid neck tension.
I exhale during the lifting phase because this helps me engage my back core concentrically. Some instructors teach students to exhale during the lowering phase to increase the backbend, but I find that this makes it more likely for my ribs to flare, and ribs should be pulled in.
If strengthening for backbending, keep arms in external rotation. Squeeze a block between hands if you struggle with this.
Arms and legs can be slightly wider than hip width, however, determine the appropriate spacing depending on your goals (generally arms should be shoulder width apart or slightly wider, legs can be together or slightly wider than hip width apart).
Core Muscles
The back core is engaged concentrically, and the front core muscles are engaged eccentrically.
Variations
Have someone hold feet in place, or hook feet under something. This will increase the range of the movement.
Push feet into a wall. This will also allow for more spinal extension.
Side Crunches
My Intention
I use side crunches to strengthen the obliques as movers.
What to look for
Try to keep the hip flexors in extension and squeeze your glutes.
Keep your spine neutral and do not let your low back arch.
Exhale during the lifting phase.
Core Muscles
The obliques on one side engage concentrically, while the obliques on the other side engage concentrically. The transverse abdominis, pelvic floor, diaphragm, and other stabilizers engage isometrically.
Variations
Bend knees and keeps legs on the ground
Use a stability ball under hips so lateral flexion can be trained on both sides in each rep
Measuring progress
Whenever I create a new workout, I make sure to include my goals for the workout and when and how to measure my progress towards these goals. For example, if you’re working on core stability to improve your invert, you should check in with your invert regularly. You can also measure your progress by recording how many reps you can do or the length of time that you can hold a particular pose for. If you don’t see any progress after a few months, it’s a good idea to re-evaluate your workout and check in with a coach.
There are dozens of other amazing core exercises. This blog focused more on core stabilization. I will eventually share a follow-up blog with my favorite core strengthening exercises. Let me know if you try these exercises or if you have any questions!
Special thanks to PT Ruby for reviewing this blog!
If you like my work, considering giving me a tip on Venmo @Jody-Ryker or buying me a coffee at https://www.buymeacoffee.com/JodyRyker
References and further reading
Applied Anatomy of Aerial Arts. Dr. Emily Scherb (book)
Flexipedia. Dr. Jen Crane & Ess Hoedlmoser (ebook)
Strength & Conditioning for Pole. Neola Wilby (ebook)
What You Should Know About Eccentric, Concentric, and Isometric Exercises. https://www.shape.com/fitness/tips/eccentric-vs-concentric-isometric-exercises
How to Do Roll Up in Pilates. https://www.verywellfit.com/how-to-do-pilates-roll-up-2704679
Concentric, Eccentric, Isometric Contractions & The Core. https://fatchfitness.com/concentric-eccentric-isometric-contractions-the-core/
4 Exercises to Rebuild Your Core After Diastasis Recti. https://www.health.com/condition/pregnancy/diastasis-recti-exercises
Abdominals & Core, Anatomy Explained. http://outfithealth.com.au/abdominals-core-anatomy-explained/
Core stability. https://www.physio-pedia.com/Core_stability
Lateral Flexion (Side Bend) is The Best Lower Back Pain Treatment. https://www.pilatesfitness.com.sg/lateral-flexion-side-bend-best-lower-back-pain-treatment/
Core players: The muscles that move your trunk and how to work them. https://sequencewiz.org/2015/10/28/core-muscles/
Stabilizer Muscles: What They Are and Why They’re So Important. https://www.stack.com/a/stabilizer-muscles-what-they-are-and-why-theyre-so-important/
Core dysfunction and lower back pain. https://dentistry.co.uk/2017/09/20/core-dysfunction-lower-back-pain/
The pelvic floor and core. https://www.pelvicfloorfirst.org.au/pages/the-pelvic-floor-and-core.html
The pelvic floor and core exercises. https://www.pelvicfloorfirst.org.au/pages/pelvic-floor-safe-core-exercises-.html
For The Love of Your Core - STOP Pulling Your Bellybutton to Spine - The Bloom Method. https://thebloommethod.com/blog/stop-pulling-bellybutton-spine
Your Hip Flexors Aren’t Tight, They’re Overworked. Here’s What to Do About It. https://deansomerset.com/hip-flexors-arent-tight-theyre-overworked-heres/
Understanding Pelvic Tilt Muscles and Function. https://www.nfpt.com/blog/understanding-pelvic-tilt-muscles-function
Meet Your Transverse Abdominus: What It Is and How to Activate It in Yoga Practice. https://www.yogauonline.com/yoga-pose-library/meet-your-transverse-abdominus-what-it-and-how-activate-it-yoga-practice
Core Training. https://lakecountrytraining.com/2017/12/20/core-training/
The muscles you never think about - until they stop working. https://www.elsevier.com/connect/the-muscles-you-never-think-about-until-they-stop-working