External core:
Muscles that lock down the spine and torso
Drawing in the belly button
Bracing and holding the breath
All very much necessary for lifting heavy weights, or if someone is about to hit you in the stomach, but not as functional for every day movements
It’s not possible to walk around holding your breath, although many folks do a version of this with shallow chest breathing!
It is also not possible to walk around with tense muscles all day. Larger muscles aren’t designed to do that. Most muscles are designed to fire and then relax, not stay tight all day. If they are tight all day they don’t receive blood or oxygen, and they hurt.
Bruce Lee in Enter the Dragon described the ideal in stabilization - “not tense, but ready” Beautifully stated! Like a cat, relaxed but ready to respond.
The external core is what folks think of when they ask for core exercises. They want to be ripped, and have visible abs. That is certainly an aesthetic, but not entirely functional.
If you are doing a bunch of external core exercises without also using the internal core then you are most likely compensating and trying to add strength to dysfunction. You might think you are doing crunches for your abs, but you are often straining your neck or (in a full sit up) using mostly your hip flexors.
Physical Therapist Gray Cook has a great quote “Stabilizers don’t do their job by being strong, they do their job by being fast.”
At Square One Fitness we want to teach you this functional core and stability. Not to be tense, but to be ready.