Deadlift form and individual morphometry

Question

I'm a beginner lifter (female) doing Starting Strength. I'm having a problem with my deadlift form that I think might be partly related to individual morphometry.

So, what happens is this: I set up as described in Rippetoe's SS with the bar at midfoot. I take my grip. I bend my knees until my shins touch the bar. Because I have (very) disproportionately long thighbones compared to the length of my torso and shin bones, this puts my hips quite low, my back at about a 45-degree angle to the floor, and my knees jutting pretty far out over the bar. It's a very awkward arrangement. When I start to pull, inevitably my knee angle "wants" to open first to the point that my back is horizontal before the bar actually leaves the ground (just like in Fig 4-35 in Rippetoe's SS). With this kind of form, I was deadlifting 1.28X my bodyweight. If I force myself to maintain the same back angle through the pull, I could probably deadlift more like 1X my bodyweight, if that. Even if I deload to just 65 lbs, it stills feels really awkward that my knees are in the way of the bar as I start to pull.

I noticed that Rippetoe does allow for substantial differences in deadlift back angle due to individual morphometry – e.g., in Fig 4-31, the leftmost stick figure's back is almost horizontal. However, like I said, when I set up according to his instructions, my back angle is actually more like 45 degrees.

So my questions are: what kind of form, especially back angle, is correct for someone with my morphometry (long thighbones)? An additional complication is that my squat is embarrassingly weak, so is it a problem of weak quads? And what should I do about it?

EDIT: Indeed, my hips are rising to near-horizontal before the bar leaves the ground.

Answer 1

When I start to pull, inevitably my knee angle "wants" to open first to the point that my back is horizontal before the bar actually leaves the ground

This sounds fine. Fully horizontal is a bit much, but lots of people get to near-horizontal and that's the way it should be. There's no need to keep your back angle constant from your setup. It's very common for the first thing after setup to be the hips shooting up before the bar comes off the ground. As long as you maintain your back's natural curve by locking the spinal erectors and the hamstrings, it sounds like this could be fine.

(The relevant figure in SS 2nd edition is 4-32, with a caption that starts, "The correct starting position (A), and the position that often gets used instead (B)." In (A) the hips are rather high and the back is significantly angled towards the floor; in (B) the hips are almost even with the height of the knees and the back is nearly upright. The point is that "the lifters 'sets up' in position A, thinking that the bar leaves the ground from there, but the hips are raised into position A before the bar leaves the ground.")

With this kind of form, I was deadlifting 1.28X my bodyweight. If I force myself to maintain the same back angle through the pull, I could probably deadlift more like 1X my bodyweight, if that.

This reinforces my belief that you're doing fine. If your back is maintaining a natural curve I'd keep on trucking.

A video of your lift would be helpful to confirm this. An in-person form check would work too, if you can find someone knowledgable in powerlifting, but I suspect you know that and no such person is available.