i dont know what gyms you guys go to,,but i hardley ever even see anyone back squatting 135 to proper depth
kh300,
my doc said that anything past 90 degrees, and the kneecap stops moving. He could tell I wasn't buying it, so he had me sit and do a leg extensions. he was right. Once the leg is in an "L" shape and your feet are parallel with your body - the kneecap STOPS MOVING. Form there, it's only the knee tendons doing the work.
Try it. Use it or not, he's got me convinced that the bottom half of ass-to-grass squats mean all that weight in on your tendon.