Squat form check

[EnergyRat]

I felt a pop in my lower back on the second rep of my second set yesterday. I didn't attempt a third set or my power cleans. I benched, did some chins and went home. My back really started hurting a few hours after coming home from the gym. It's now the next day and I can't bend over at all without significant lower back pain. Even walking is uncomfortable.

Does it look like it was caused by poor technique?

First Set: First Set - YouTube

Second Set: Second Set - YouTube

I'm 34 years old, 6"2, 105kgs, working sets were 114kgs.

Thanks

[Ryan Arnold]

Several things going on here:

1) You are overextending your low back. Do you see how your chest expands when you get your breath? Don't do that. Get your breath like someone is about to punch you in the stomach.
2) Look down. Otherwise this will lead to....
3) You are lifting your chest on the way up. Keep your chest down and drive your hips the whole way up. Lean over more.

[EnergyRat]

I can see that now. Thanks for your help, I'll take a bit of a reset and work on that.

[EnergyRat]

90kg x5 - YouTube

Does this look any better?

[Daryl Geerts]

You are bracing your abs better and not getting the overextension.

You are still lifting your chest on the way up. stay in the hips.

Put your belt back on.

[Roy Thomas]

90kg x5 - YouTube

Does this look any better?

Daryl is right, the overextension is gone. Your grip is good, you're looking in the right place, and they're all to depth.
As soon as you've gotten into the hole you need to think about shoving your ass straight up.
We get this little whisper of hip drive for the first inch or two out of the bottom. You can see this by the very mild change in your back angle (The angle formed by the floor and your back) on the start of the ascent (the back angle becomes closed).

This is good. That angle should be preserved until you are basically finished with the rep.

Right after this initial change, you stop pushing the hips up and raise the chest instead (i.e. the back angle opens).

[EnergyRat]

Great, thank you both for the responses.