To give you some background about myself:
-28 years old
-6'2'' and 170 lbs
-body fat percentage of ~14-15% measured via tanita scale and accumeasure
-2x/week on an elliptical for about an hour
-1 hour of pretty strenuous pilates/week
Despite the above, I've developed a pretty uncomfortable distended stomach. What I mean by uncomfortable is that it's unpleasant to wear anything tight around it and I accordingly have to wear, generally, 36 inch pants pretty loosely over it. It doesn't seem to be bloat from food since this distension is pretty constant. I don't have amazing digestion, but even if I stick to a really really simple diet (even an elemental diet for weeks), it doesn't help the distension (i.e. passing gas / moving my bowels doesn't help that much either). This tends to make me think this is muscular in origin (though perhaps having slow/poor digestion may have contributed to this forming in the first place). Further, I have some trouble urinating, i.e. it's tough for me to get all my pee out and this difficulty seems to possibly be related to this distension (also, I've been down to as low as 9% body fat using the same measurement methods as above though this didn't help my distended abdomen).
-Doing pilates might have made it slightly worse if anything. I've tried stomach vacuums, though they don't seem to have helped at all.
-I've enclosed a few pictures and a video of my distended abdomen to give you guys a sense of the distension. In the video, I flex/vacuum in my abdomen during part of it to give you a sense of the range, though the full distended look is when my gut is relaxed. It doesn't seem to be fat, as I can't "pinch" any significant quantity on my gut.
I'm wondering what could be the cause of this and what I could do to fix it.
Is there any benefit to using any sort of "waist trimmer"/corset type device or does that just end up weakening those core muscles instead of tightening/retraining them?
Is there some optimal method to doing vacuums and/or am I substantially overbuilt/imbalanced in the way my core musculature has developed?
Thank you guys