Let your knees come a little more forward. Wear a belt.
I'm on the 2nd week of The Bridge and I just wanted to get a check on my 303 squats. The form looks good to me but the reason I'm asking for a critique is that past 6 reps, my LOWER back is on fire. Not the feeling of pulling or tweaking a back, but the muscles are literally cramping. I barely mustered the courage to do my 4th and last set after this. Then for about an hour after my lower back felt extremely rigid and on fire. Luckily after that it went away magically and today I feel great with my back just a little sore. My wife felt the same thing, but just not to as bad of a degree.
I think I just had the equivalent of a bicep bro pump but in my lower back. It 'hurts' since its on a more sensitive part (lower back), but I swear thats what it feels like. Is that just par for the course for these type of higher rep tempo squats or is there something glaringly wrong with my form?
Just a few things I wanted to point out that I am aware of:
1. I recognize my ascent was closer to 2 seconds than 3 seconds. Seems like time travels faster under the bar.
2. I recently changed back to doing Low Bar squats again from High Bar.... Thats why I have the foam roller there. Making sure I stay in my hips, versus the quad dominant High bar technique.
Let your knees come a little more forward. Wear a belt.
It could mean that, it could also mean that you're using your quads too much.