SS squat hip drive explanation

[jsiggy]

Rip,

Love the new SS book, but I've got a question about muscle involvement in hip drive. SS talks thinking about raising the butt up out of the bottom to involve the hips, even saying that it's normal if the butt even rises a little faster than the shoulders initially. I'm sure I'm missing something obvious, but it feels like when my butt rises faster than shoulders, I am using more quads and less hips. An extreme example would be butt going up and shoulders not rising at all - which feels like almost all quads. I expected that more hip (meaning primarily glute and hamstring, right?) would mean the angle between the femur and torso would be increasing more rapidly. Can you clarify for a kinesiological idiot?

[Mark Rippetoe]

If your butt rises faster than your shoulders (I assume here that you mean your back angle became more horizontal) and you feel your quads, your butt has gone backwards more than up. You have opened your knees more than your hips. But I doubt that this is the case, so I'll need to see a video.