Core Training Is More Than Abs
Bracing, breathing, and resisting unwanted movement.
When people think "core," they usually think abs and crunches. But the core is better understood as a system that helps you position your trunk, transfer force between your upper and lower body, and resist movement you don't want.
What the core does
- Trunk positioning
- Force transfer between upper and lower body
- Stabilization
- Resisting unwanted movement
Bracing and breathing
Bracing is creating tension around the trunk to support a position. Breathing is part of that—how you breathe affects how you brace, and holding your breath through everything isn't the goal.
KBRI uses A-R-C breathing as part of its coaching framework. For the specifics of A-R-C, go straight to Kelsey's own explanation in the Foundations series rather than a written summary.
The core's jobs
Anti-extension
Resisting the low back arching. Examples: planks, dead bugs.
Anti-rotation
Resisting twisting. Example: a band or cable press held away from the body.
Anti-lateral flexion
Resisting bending sideways. Example: carrying a weight in one hand.
Controlled flexion / extension
Moving the spine with control where appropriate—not something to avoid entirely.
Why endless crunches aren't the whole picture
Crunches train one thing: trunk flexion. There's nothing wrong with them, but doing hundreds doesn't develop your ability to resist extension, rotation, or side-bending—which is a lot of what your core does in daily life and lifting.
Don't put strength on dysfunction
This is a core KBRI principle. It means prioritizing movement quality, positioning, control, and appropriate progression before simply piling on external load.
It isn't a diagnosis, and it isn't about being "broken." It's about building a foundation you can actually load well.
This is general education, not an assessment or diagnosis. If you have pain or a medical condition, check in with a qualified healthcare professional.