There is no empirical evidence of atg squats being bad for the knees. If you are going to be doing Olympic lifts then squat ATG and make dang sure it's done right and the lifter is properly spotted.
As for PC vs HC, we do both. PC develops power from the ground up, but the HC develops explosion and a more powerful hip action, all of which are important in just about every sport.
http://weighttraining.about.com/b/2008/05/13/how-low-should-you-squat-full-or-parallel.htm
As for PC vs HC, we do both. PC develops power from the ground up, but the HC develops explosion and a more powerful hip action, all of which are important in just about every sport.
http://weighttraining.about.com/b/2008/05/13/how-low-should-you-squat-full-or-parallel.htm