16: The Deep Core How the Transverse Abdominis, Multifidus and Diaphragm Keep You Stable from the Inside Out
When people talk about the core, they usually mean the six-pack muscles or maybe the obliques. But the real workhorses of core stability are the deep muscles you can’t see the ones that keep your spine centred, your posture strong, and your movement smooth.
These muscles don’t generate power. They prevent excessive motion, manage internal pressure, and provide a foundation for everything else. If you want real, lasting control not just short-term strength you need to train the deep core unit.
Meet the Deep Core Team
1. Transverse Abdominis (TVA)
This is your body’s natural weightlifting belt. It wraps around the midsection like a corset and provides 360-degree tension and support.
Activates before limb movement in healthy individuals
Helps stabilise the lumbar spine
Works with the pelvic floor and diaphragm to manage intra-abdominal pressure
2. Multifidus
These small spinal muscles sit along your vertebrae and stabilise segment by segment.
Controls small spinal adjustments during movement
Protects against shear forces
Often inhibited after back pain or injury
3. Diaphragm
More than just a breathing muscle it’s a key part of your core cylinder.
Works with the TVA and pelvic floor during bracing
Supports spinal stiffness through proper breath mechanics
Poor diaphragm function leads to overuse of chest and neck muscles
Why These Muscles Matter
When the deep core is functioning well:
You move with less compensation
Your spine stays protected under load
Your breathing supports your bracing
You feel more connected and stable in dynamic movement
When they’re not:
You overuse your lower back and hip flexors
Bracing feels shaky or uneven
You lose power in lifts or struggle with balance
Postural fatigue sets in faster
How to Train the Deep Core
1. Start with breath work
Diaphragmatic breathing is the gateway to deep core control.
Lie on your back or sit against a wall
Breathe through the nose into the belly and ribs
Avoid chest rise aim for full 360-degree expansion
2. Isolate and activate
Use low-intensity, high-awareness drills to reconnect with these muscles:
Supine TVA contractions (draw the belly in gently, without holding your breath)
Bird dogs with slow, controlled limb movement
Quadruped rock backs maintaining neutral spine
Modified dead bugs with breath control
3. Add resistance and integration
Once the deep core activates correctly, integrate it into full-body movements:
Pallof presses
Carries (suitcase, front, offset)
Single-arm overhead presses with braced trunk
Plank breathing with TVA engagement
4. Rehab? Start here
If you’ve had back pain, surgery or core dysfunction, this is where recovery begins. Don’t jump to crunches or loaded work without rebuilding this foundation first.
Final Thought
The deep core muscles are quiet, but powerful. They work in the background to create the kind of stability that prevents breakdown and allows your larger muscles to perform at their best.
Training these muscles is about connection, not intensity. Slow it down. Breathe well. Build stability from the inside out and you’ll move better in everything you do.
