Butt wink issue

[StartedStrength]

Dear mark,

I have read your book and loved it. Helped me a lot.

I perform a full squat as you advised. My issue is butt wink when reaching full motion. I have read tones of articles about the subject and watched a huge amount of videos and it did not give me the information I was looking for.
Thats why I ask you. If i am doing everything you said A lifter should do, what could be the problem? I dont want my back to start giving up on early stages of life. Is this a flexibility issue? Genetically? I am not talking about neutral spine like you say its reasonable and OK, I am talking about a more prominent one.

Thanks ahead. Have a great day.

[Scaldrew]

First off, lumbar flexion, not butt wink. Pls, never again. Ever.

Second, video?

Thirdly, and this is just my bet, but you're probably going too low. You want to squat just below parallel, not "ass to grass" or 2 inches below parallel. Your hamstrings reach the end of their extensibility, slack at the proximal (hip) end, and your back goes "WOOP I"m round now". It's science. Stop a little higher.

How does one do this, you ask? Think about going up while going down. This will cut your depth off a little short. Don't take that as an excuse to squat high; above parallel is the other extreme. Keeping this cue in your mindbrain will also tighten everything up as you descend which is always nice. It's better to bounce on tight muscles in a controlled fashion than to just drop into the hole like it's nobody's beezwax.

[StartedStrength]

So what youre saying is to stop where the tilt begins?

[Scaldrew]

Yeah, sure. Just stop a little higher. You don't have to "bottom out". Hip crease just below the knee, bounce upwards (not forwards or backwards), and you're golden. If you're still unsure, post a video.

[djsilvera]

Shoving knees out to keep the thighs from interfering with the pelvis at the bottom is important as well. If thighs are interfering with the full hip extension it could cause the lower back to round.

[Brodie Butland]

So what youre saying is to stop where the tilt begins?

No, stop before the lumbar flexes. But keep in mind that lumbar flexion and an appearance of change in the lower back are not the same thing...you can have "butt wink" and still have lower back extension. That's why we don't use the term around here.

Without a video, I have no idea if you're going into flexion or not.