Core Stability and Rib Stacking: Common Questions About the Core
By Dr. Brooke Munion, Chiropractor
Most people have heard it’s important to strengthen the core—but why? When asked, many people aren’t entirely sure. It’s just something they’ve heard they should work on.
Here’s the truth: having a strong core is about much more than aesthetics. A strong, stable core is essential for everyday life. It helps us maintain posture when lifting, move with greater ease, and protect our body from unnecessary stress or injury.
What Muscles Make Up the Core?
Hint: it’s not just your abs!
Core muscles as an analogy of a stable cylinder.
The core is made up of four major muscles that form a cylinder:
Diaphragm
Multifidi (deep spinal stabilisers)
Transverse abdominus
Pelvic floor
Together, these muscles create intra-abdominal pressure, which stabilises the spine and pelvis. The best analogy? Think of your core like a soda can: it has a top, bottom, and sides that keep it strong and pressurised.
What Is Rib Stacking?
Rib stacking is about positioning your ribs directly over your pelvis (your hip bones/ASIS).
When stacked: the core is in an optimal position to maintain pressure, stability, and strength.
When flared: the ribs lift up and out, creating weakness and forcing compensation in the lumbar spine.
Depicts A) Optimal Positioning/ Activation and B) Shows Rib Flaring
What Happens When You Breathe?
Inhale: chest expands outward, diaphragm contracts down, belly rises.
Exhale: chest contracts inward, diaphragm relaxes upward, belly lowers.
This breathing pattern creates and regulates intra-abdominal pressure—the foundation of core stability.
Why Does Rib Position Matter?
When ribs are stacked correctly, the core functions like an unopened soda can: it can withstand force without collapsing.
But when the ribs flare or pressure escapes, the system weakens—like a cracked can. This increases the risk of injury, strain, or compensation in other areas.
Too much pressure can also be problematic, leading to issues such as:
Hernias
Disc bulges
Pelvic floor leakages (urine)
How Does the Pelvic Floor Work With the Diaphragm?
The diaphragm and pelvic floor work like a piston system. As you breathe, they coordinate to manage pressure in the intra-abdominal cavity.
If this pressure isn’t managed properly, it often escapes to the weakest area, which may cause:
Diastasis recti (DR)
Pelvic floor dysfunction
Hernias
Low back pain
Hip instability
This is why learning proper rib stacking and breathing techniques is so important—not just for athletes, but for labourers, new mums, and anyone wanting to protect their body long-term.
What Is the Pelvic Floor?
The pelvic floor stabilises the pelvis and spine, supports abdominal organs, and helps maintain continence.
It’s made up of three layers of muscle:
Urogenital triangle
Urogenital diaphragm
Pelvic diaphragm
Key muscles include the levator ani group (pubococcygeus, puborectalis, iliococcygeus) and the coccygeus.
Core stability is more than “doing ab exercises.” It’s about the coordination of the diaphragm, ribs, pelvic floor, and deep stabilising muscles working as a system. By learning rib stacking and proper breathing mechanics, you can build a strong, functional core that protects your spine, improves performance, and reduces risk of injury.
