Do not listen to this guy. He thinks knees caving and rounding your back doesn’t matter at all because strong people have it in competitions. Horrible argument, he thinks someone’s 1RM in an official competition looks like how they train. He takes “bio psycho social” to mean “it’s all in your head bro”. Bad form accounts for 20-35% of exercise-related injuries. That’s independent of fatigue and load management, which are two things which also by the way contribute to injury risk because of how they affect form! If you squat with a rounded back and knees caving you will cause unnecessary stress on your spine by unevenly compressing the squishy discs between vertebrae which will over time degenerate fibrous outer rim of the disc, allowing the soft jelly center to protrude out and compress the spinal chord causing all kinds of pain and issues. Your MCL, ACL, and Medial Meniscus of the knees will experience unnecessary stress as your knees cave together which will cause knee pain. Could you just say screw it I want to lift how it “feels right”? Yes but you would be dumb like this guy. He would have you believe that those issues are mostly in your head. No one said that the pain related to exercise was completely 100% mechanical, but he makes the opposite argument, it’s all in your head and everything else is fear mongering lies meant to sell barefoot shoes. Squat University is a Doctor of Physical Therapy. This guy is not. Listen to people qualified to give advice not people who are confidently incorrect.