I agree with Commander_Bush, always do it on the smith, unless your very experienced.

Did you use guards?? Or were you doing it completely free? I mean, in the squat rack, there should be those two metal bars that run acroos the sides right....so when you feel your done, and you can't push up, then like KeyMastur said, you have to slowly squat DOWN, until the bar rests on the two gaurds!!!

Speaking of squats, I saw this one kid in my university set up the squat rack, he puts on 315!!!! This kid is no more then 170 pounds of weight. He gets under the bar, lifts the bar up, his legs are WIDE apart, probably about a meter apart, and he squats down about 10 inches, and then goes back up!!! WTF is that?????????????????????????????????