Hey man, overall I really like your squat and don’t actually see that many issues. I can tell you watched some Rippetoe videos, but I’m glad to see you didn’t buy into them completely.
What I like:
You sit down: I know Rip recomends to sit back, but it’s just not optimal for the raw squat, his reasoning being that you take advantage of the strong hamstring and glute muscles, but this simply makes no sense. First, the hamstrings don’t actually contract during the squat, their a hip extensor and a knee flexor, both happen during the squat and they oppose each other, so they wind up in an isometric contraction and act more as a stabilizer muscle. The glutes while the main hip extensor aren’t a prime mover when you go below parallel, they’re fully engaged at parallel however. The big limiting factor of most squats are the quads, and when you sit back you take all the torque off the knee extensors and get less stretch reflex, so a weaker contraction, meaning you can’t get out of the hole with what your potential is.
What you’re doing is sitting straight down, and letting your knees travel forward, this loads the quads very well, and will get you out of the hole so that the glutes can take over and extend your hip.
What you can improve on:
Hamstring flexibility: your flexibility is basically the only issues I really see. Your pelvis isn’t rounding that much, but your low back is, both are caused by the hamstrings being short, which is very common in just about everyone. I’ll provide a video of some warm ups you can do that should really help out.
Hip flexibility: from your back angle, I see you shifting as you get to parallel. There are 2 causes to this, 1 is tight hips, or rather a hip that’s tighter than the other. Iron that out, and I feel you’ll be much more comfortable below parallel. Once again, this will be in the video I provide.
Glutes : this is the other reason you could be shifting, below parallel, the glutes are still active, just not to the degree they are above parallel, so if one is weak, ie your left glute in particular, you’ll shift and put the stress on the right one. I’ve had to iron this out myself.
Single leg hip thrusts are a great option, start with 20 each leg a day, and try to progress to 100 every day for a week or two, the glutes are super hard to over train and it won’t hurt your lifts at all.
What you can think about:
Head position: you look down, I’m assuming that’s a Rip technique you learned. I can’t personally do it, but it doesn’t make it wrong, I hear it’s good for maintaining a neutral spine. You can consider looking straight ahead, but keep with the head drive you’re using, that was another thing I liked, you drive your head back into the bar when you start to stand up.
Bar position: Looks like you’re going low bar, and it works for you, you have fairly short legs and a long torso, and stay upright. You can try a higher bar position out, but it may not be optimal, and I don’t mind someone with your build staying low bar if they stay upright and get their knees forward.
Shoes: if you have the opportunity at all, get weightlifting shoes. They make such a huge difference and feel like squatting on a cloud compared to bare feet. You’ll get depth much smoother, put more emphasis on the quads, and stay more upright.
Hope that helps man, overall good squats, and here’s the video. Do this warm up daily, or at the very least before you squat, it should make all the difference in the world.
There are a few iso machines for hamstrings at my gym I’ll do some research and get on it. Thanks man.