What muscle is allowing me to move my stomach?
I've been curious about this for years and all my friends treat me like a freak for this. As a little kid, my mom would make me laugh by having me chug water and the shaking me around so I could hear it slosh. I thought it was so funny, I learned to do it voluntarily with no external force. I'm in my 20s and can do it at will. If I've had anything to drink you can clearly hear it move around.
My abs don't look like they're flexing at all, and they stay soft to touch while doing. I can breathe normally while doing it, though it impacts exhalation just enough to make my speaking sound weird. I think I've been inadvertently working out my deep core by doing this for years and years as I've had a baby and my doctor would comment at each appointment that I had the strongest core she had ever seen.
Would I be able to move the transversi abdominis without moving any of the surround muscles? And are those muscles able to be easily moved side to side?