No. That's not how these muscles work when you lift heavy weights.
And I'm not talking about the liposuction kind. I'm talking about the one where you 'suck in your navel in toward your spine' exercise; the thing that some insecure men do when a pretty girl walks by them on the beach. Have you ever found those useful for strengthening the transverse abdominis?
No. That's not how these muscles work when you lift heavy weights.
Are those muscles ever supposed to work like that?
Where did that even come from? I remember in Junior High Football we used to lie on our back and do those, never figured out why.
I can't tell you how many times I've had to get clients to unlearn and forget about this nonsense. "Drawing In", as it's called, is to the NASM what Hip Drive is to Starting Strength.
It's ridiculous how much time and energy some of these NASM guys spend trying to teach this stuff to their clients. Of course the clients never really understand why because it feels weird, doesn't help with anything, and is basically un-natural to perform under load. Of course, NASM solves this problem by eliminating the whole "under load" part of the equation. That complicates their model of training - or whatever the hell it is.