The video below claims that this is "Olympic" lifting versus powerlifting, but the distinction is pretty facile. The actual difference is between proper squatting and half-repping:
I may have pointed out before (several times, actually) that I cannot stand half-reppers. Squatting down to a depth of maybe 4 inches is a crime against humanity and those who commit it should be shot. Or, barring that, tasered in their vaginas and summarily tossed out of the squat rack, if not the gym.
It annoys me exceedingly to walk into my gym and find some dumbass taking up my squat rack with four plates on the bar and doing half- or quarter-squats. This is true for just about any real lifter.
Now, I certainly do not claim to have perfect squat form. There are times when I am repping out 250lbs or more where my hips sort of "shift" when I am getting "out of the hole", and as a result a bit more lateral stress than is strictly necessary is placed on one or the other knee. That is bad form, but it is also a small technical detail that I know is a problem and try to fix.
The one thing that I have spent a lot of time over the past year or so trying to improve is my squat depth. I used to think that going down to parallel was "good enough" - but at some point last year, I decided to see if I could squat deeper and improve my strength and form as a result.
That is, of course, precisely what happened.
The fact is that the deeper you squat, the stronger you become. Real powerlifters and strongmen - like, say, Mariusz Pudzianowski, five-time World's Strongest Man champion and all-round epic badass, can show you a thing or two about how to squat insane amounts of weight with superb form:
My friends, if you use a squat rack, and you insist on half-repping, do not be surprised when guys like me, who look like we actually know what the hell we're doing in the gym, give you some serious stink-eye. You befoul the sacred and holy Temple of the Iron God with your weak and lame presence. Verily, begone! And let the true Iron Priests work to uncover the Riddle of Steel!