vtech's got it right...I have dont smith squats before, maybe 20 sets total in my 4 years of training. Stick to free weight squats, they are one of the best exercises out there and by doing them on the smith machine you kind of defeat the purpose(you turn it into a hack squat variation). I could def. free squat a lot more than smith because smith puts too much pressure on your knees, i would never go heavy with that.