First off,my program isn't for trainee's that are natural.This is a rather advanced program.
Another thing you need to take in consideration is,I only use 2 sets per body part.High intensity/low volume.So over working my secondary muscle isn't an issue by any means.I could see your point if I was doing 8-10 sets per body part.Not the case here.I also have muscle maturity on my side as well.
Have you ever seen the studies done by the Bulgarian Olympic team?They used to have their power-lifters train 1 body part 6 x in 1 day.That's right,6 times in one day.It's all about rest and proper nutrition.
Certainly after my morning training session I'm exhausted even doing 2 sets per body part.But the rest of my day is devoted to proper nutrition and supplements like liquid amino acid/glutamine ect.
So for me,this is by far the best routine I've ever used,with the exception of the 3 day split combining back/bi's ect in 1 session.
~Pinnacle~