When most people hear the word "core," they picture sculpted abs and endless crunches. But your core is so much more than a six-pack. As a pelvic health physical therapist, one of the most important conversations I have with clients is helping them understand their inner core system — a team of deep muscles that work together to stabilize, support, and protect your body from the inside out.

Let’s break it down.

What is the Inner Core?

Your inner core is a deep muscular unit made up of four essential components:

Diaphragm
Pelvic Floor Muscles
Transversus Abdominis (TrA)
Multifidus

These four parts work together in a coordinated way to support your spine and pelvis, regulate intra-abdominal pressure, and form the foundation for safe movement.

1. Diaphragm: Your Breath Muscle

The diaphragm is the dome-shaped muscle at the bottom of your ribcage. It’s the primary muscle of breathing, but it also plays a key role in your core.

When you inhale, the diaphragm contracts and pushes downward, allowing the lungs to expand. As it does this, pressure increases in your abdomen and your pelvic floor moves downward. The rest of your inner core responds to that pressure, creating stability and support for your spine.

Breathing patterns affect pelvic floor and core coordination — which is why breathwork is a foundational part of pelvic health PT.

2. Pelvic Floor: The Floor of the Core

Your pelvic floor muscles form a hammock-like support system at the base of your pelvis. They hold up your pelvic organs, control continence, play a role in sexual function, and contribute to core stability.

They respond to pressure changes created by the diaphragm and help regulate intra-abdominal pressure. When this system is disrupted, issues like leaking, prolapse, or pain can arise.

3. Transversus Abdominis (TrA): The Deep Ab Layer

Often called your "corset muscle," the transversus abdominis wraps around your torso horizontally. It’s the deepest layer of abdominal muscles and activates before any limb movement to stabilize the trunk.

TrA is critical in postpartum recovery, back pain rehab, and athletic performance. But it doesn’t work in isolation — it relies on coordination with the pelvic floor and breath.

4. Multifidus: The Spine Stabilizer

These small, deep back muscles run along your spine, providing segmental control and support. Though they’re less famous than other core muscles, they’re vital for spinal health.

The multifidus engages with the TrA and pelvic floor to maintain upright posture and protect your spine during movement.

Why the Inner Core Matters

The inner core is the foundation of movement. When these muscles function in harmony, they provide:

Spinal stability
Pelvic support
Efficient movement mechanics
Reduced risk of injury

But if one part of the team isn’t working well — like a weak pelvic floor or shallow breathing — the whole system can become dysfunctional.

Pelvic health physical therapy focuses on retraining this system. Through managing intra-abdominal pressure, breathing mechanics, motor control exercises, posture education, and hands-on techniques, we help clients rebuild strength from the inside out.

Final Thoughts

Core strength isn’t about how many crunches you can do — it’s about how well your body coordinates its inner support system.

Understanding your inner core is empowering. It can help you move better, feel stronger, and heal smarter.

Want to learn more? Reach out for more tips on pelvic health, mindful movement, and all things core. If you have any core weakness or pelvic pain please give us a call so we can schedule an evaluation!

Your Core Isn’t Just 6 Pack Abs — Let’s Talk Inner Core