Their form looks bad to you. You'll lose form when you're lifting near to max effort.
The form looks bad to me b/c it is bad. You do lose form at max, but it should be in the fullness of contraction, not moving in ways that are very dangerous.
There are a couple different styles to squatting. Every lifter has different hip/back mobility. They have to choose one that'll help them get low enough to get the green light in a competition meet.
There are different styles, but that in no way means those styles are are safe. Most every person should (ideally) have almost the same hip/back mobility:: in reference to the squat, feet a little more than shoulder width apart, feet pointing straight or nearly straight ahead, head up, feet flat on ground weight equal on toes and balls of feet all the way down till thighs are nearly parallel to the floor. Many people can't do this b/c they have overactive/underactive and not flexible enough muscles.
It's called Boxed squat. Helps your body get used to being under heavy weight & strengthening the assisting muscles for squats.
And the sudden stop (like the guys in the video are doing) puts alot of strain on the spine. Additionally, if the lower back comes out and the butt comes in, as opposed to maintaining the natural s curve of the spine, it misaligns the spine and further promotes injury (of course greater strain with more weight).
To an untrained person yes it looks very dangerous. Look at Olympic lifters, they lift heavy weights gracefully over their heads. It takes years of practice to get your form down correct. Even with basic lifts like bench,dead,squats.
I said nothing about the fact that they're lifting heavy weights. I mean, of course lifting heavier weights is inherently more dangerous than light, but my point had nothing to do with the amount of weight and everything to do with the form of lifting that weight.
The reason I mention it is b/c the study and improvement of alignment/movement is a hobby of mine. Additionally, my girlfriend is a certified personal trainer, and is currently working on her certification for injury rehabilitation and the study of how the muscles should move, and body should be aligned, to heal and prevent injury.
