Mark Ottobre explains why your squat bottoms out with a butt wink: your core isn't weak, it's not controlling your pelvis. High ab volume won't fix it. He shows drills to teach your core to stabilize under load instead.
I get you to do a bodyweight squat. Your bum to your ankles, go all the way down. Let's have a look. Okay, cool. When you go into that full squat, right, what happens to begin with is that you actually lose control through your abs. You've got quite a bit of a butt wink, right? So that means your core's weak. When I ever say weak, people go, oh, but I do so many abs, I've got a strong core, right? And yes, you do, right? But I'm not talking about your core being weak in the sense of how much you train it. I'm talking it being weak in your ecosystem, right? It is a weak link. So when you go into this position, it's not maintaining your pelvis and you're having to dip into that butt wink, right? So that is an area of unlock for you, which I'll show you some drills before training, help your stability, teach you stability, because it's not— again, it's not like so much you're weak, she's not activating the right position.
