top of page

The Most Overlooked Core Muscle And How To Access It

Belly Breathing, Diaphragmatic Breathing, Core Stability, Core Strength, Lower Back Pain, Core Tension,

When you think about strengthening your core, what comes to mind? Do you think about different types of exercises like planks or sit-ups? Maybe you think about wanting your abdomen to look a certain way, like having six pack abs or a flat stomach? Or maybe you've been told that you need to improve your abdominal strength to reduce low pack pain?

Belly Breathing, Diaphragmatic Breathing, Core Stability, Core Strength, Lower Back Pain, Core Tension,

While none of these ideas are wrong, they don't tell the whole story. We assume that if we have strong abdominal muscles, we'll have a strong core. But, this is not always the case. One of the most important aspects to your core strength isn't your abdominal muscles. It's your breath! Specifically, inter-abdominal pressure created through diaphragmatic breathing creates core stability.

In this blog post, we'll explore how your breathing patterns impact your core stability, and how to assess if your own breathing patterns are supporting, or hindering, your core strength. Don't miss the 10-Minute Tune-Up at the end of this post, Core Stability From The Inside Out, to put these lessons into practice.

Let's begin with the word core, which implies center. When you hear "apple core", you don't think about the outer skin of the apple. You think about the center where the seeds are located. Apply this to your abdominal core. Think about your "core" as a deep internal structure that supports your torso, not just the distal abdominal muscles that surround it.

While part of your core certainly includes your muscles such as the rectus abdominals, the obliques, and the transverse abdominals, the lesser known core muscle is your thoracic diaphragm. Your thoracic diaphragm is a dome shaped muscle that sits at the bottom of your ribcage. It's often referred to as your breathing muscle because of its roll in respiration.

Thoracic Diaphragm 101:

The thoracic diaphragm separates the top part of your torso from the bottom part of your torso. Imagine a flat horizontal muscle that spans the entire width of your torso, sort of like a fitted bed sheet attached to the bottom of your rib cage. This muscle moves up and down as you breath, like a jellyfish moves up and down through water. Your lungs and heart rest above the thoracic diaphragm, and your abdominal organs rest below it.

Thoracic Diaphragm In Relaxed State
Thoracic Diaphragm In Relaxed State

When you inhale, your thoracic diaphragm contracts and moves down. This creates negative pressure in your chest, which is what pulls air into your lungs when you inhale. This also creates slight pressure in your abdomen, which is why your abdominal organs push out a little when you inhale. Side note - this is why we call it belly breathing! Check out more about belly breathing, in last week's post, Three Problems With Your Belly Breath And How To Correct Them.

When you exhale, your thoracic diaphragm relaxes and moves back up towards your chest, like the image shown to the left. This pushes air out of your lungs, and your abdomen draws back toward your spine.

The way the thoracic diaphragm moves up and down is directly correlated to how the pelvic floor diaphragm moves up and down. Your pelvic floor diaphragm refers to the sling of muscles that hold up your pelvic organs. Everyone has a pelvic floor, and while this is not the focus of this post, it's important to understand the basics of how its function connects to breathing and core stability.

Thoracic / Pelvic Diaphragm Connection:

Thoracic / Pelvic Floor Diaphragm
Thoracic / Pelvic Floor Diaphragm

When your thoracic diaphragm contracts and moves down, your pelvic floor diaphragm relaxes and moves down to accommodate the internal pressure. On the flip side, when your thoracic diaphragm relaxes and moves up when you exhale, your pelvic floor diaphragm contracts and moves up to support your pelvic organs. They move in the same direction, but have opposite contract and relax patterns. Lather, rinse, and repeat, over and over again, for your entire life. The average person takes over 20,000 breaths per day. Wow!

The Soda Can Analogy:

Now imagine that your core is like a soda can. The top of the can is your thoracic diaphragm, the bottom of the can is your pelvic floor diaphragm, and the outer cylinder of the can are your abdominal muscles and lower back muscles that wrap around your torso. This is often referred to as your "core canister".

Everything inside the soda can is inside your abdomen. In addition to the obvious organs and bones and connective tissue, recall the inter abdominal pressure that is created during respiration via the thoracic diaphragm? That pressure is ALSO inside the soda can.

A full can of soda is really hard to crush. It's very strong and stable. However, if you open the soda can, release the carbonation pressure, and pour out the liquid, the can is quite easy to crush.

Now, imagine that your core is like a soda can. Keep your core pressurized, and it will be strong and stable. If you have too much pressure on the front of the back, you risk issues like abdominal hernias or disk herniations. Too much pressure on the top or the bottom can cause discomfort like heartburn or incontinence.

The Low Back Connection:

Your lumbar spine is located in your core canister. When you learn to create inter abdominal pressure during core exercises like planks or dead bugs, this actually stabilizes your lower back. While having strong abdominal muscles is important to support your lower back health, one might argue that your ability to breath optimally with your diaphragm is more important for the foundation of pelvic/lumbar stability.

Have you ever seen weight lifters wear belts? While those belts do provide some support around the core canister, they also increase the pressure on the abdomen while lifting. When you breathe with your thoracic diaphragm, and you do it correctly, your lower back is supported.

Putting It Into Practice: Core Canister Pressure

We've created a free 10-Minute Tune-Up, Core Stability From The Inside Out, below. Class explores how to use diaphragmatic breathing to create an internal pressure system, laying the foundation for core stability. With practice, you'll improve your ability to balance core tension with movement and breath. You'll not only feel the benefits of a more integrated core, but you'll also improve your posture and health of your lower back! Follow along, right at your desk and revisit this class anytime your core needs a little boost.

If you enjoyed this post, please subscribe to our newsletter to receive weekly 10-Minute Tune-Ups and wellbeing inspiration. These classes are quick office-friendly chair yoga and meditation breaks to get you moving, breathing, and de-stressed - no change of clothing or equipment needed.

Happy Breathing,

Katie Rowe Mitchell

Co-Founder + CMO Unfold and Unfold Digital



bottom of page