This is merely something that popped into my head while reading through more articles written by more "experts" about how you should handle your body..
So, you read and hear so much about working in rep ranges of 1-5, 6-8 and 12+ and how those different ranges work different muscle fibers. 1-5 is heavy to build strength, 6-8 is medium for size and 12+ is light for endurance. If I'm lifting a 5x5 chest routine on Monday, who's to say that I can't go lift a 6-8 medium weight rep range for chest on Tuesday because I'm hitting "different muscle fibers" and that be all the chest I do that week. According to the "experts", you would be hitting different fibers, so doing chest two days in a row shouldn't matter(right?), and you would be gaining size and strength at the same time. Then you could turn around and do the same for back and legs on Thursday and Friday. I'm saying all of this with a dash of sarcasm intended because I'm sick of seeing people argue constantly about over training and how what rep ranges work what and what you can and can't do on a daily basis. According to their theories, this should work, but somebody would argue that it wouldn't, simply because you are hitting chest two days in a row without adequate recovery time.
P.S. - I don't really believe in "over training" in the sense that people now speak of it, seeing as my grandfather build cinder block houses from the ground up day in and day out his whole life and had arms as big around as my legs well into his 80's.