I finally decided to try box squats today (with a bench, not a legit box). When fully down, my knees were probably an inch higher than my hips, and my numbers were awful. I was struggling (with pretty awful form I might add ) to get up 245x3, when normally I can do that with 315 to parallel. Are these just significantly harder because of the broken eccentric/concentric movements, or am I just being a bitch? Also, the trainer there told me never to go below parallel on squats... is this really a common belief?