Beginners usually do not need such advanced concepts simply because as a beginner, pretty much anything will work as it's new to your body. You don't need to bump up the intensity because the workout itself is usually hard enough. But for those who have worked out for quite some time, doing a simple routine doesn't cut it. And for those who are entering a competition and may be on low card, sub-maintenance calories and doing cardio twice a day, adding more and more weight is easier said then done. Where's the energy? That's where some advanced concepts come into play.