This post by Casey is a comment on how transitionng to fullbody must be walked into gradually. Even for an advanced lifter, you can not just jump into wholebody headlong.
Originally Posted by Greg1975
It's been about about 2 weeks now, and my CNS is flat busted...
CNS fatigue has been a huge problem for me transitioning into this program. I've been frustrated by my body's inability to adapt, because I'm certain increased frequency is the way to go from personal experimentation.
I'm starting to get a cold as I type this, and probably won't be in the gym for a week. So if anyone is going to just jump into H/L/M I advise doing it gradually and cautiously as Casey advises above. Unfortunately I'm a bit of an extremist, and I leave it all in the gym every time I go. It's been too much for my system.
That's probably the biggest trap advanced trainees fall into when trying full-body routines - too much, too soon. It's very easy to underestimate the systemic impact of what you're doing because you're "only" training three days per week. But, quite obviously, those three days are enough to wipe out even advanced trainees who are accustomed to much systemically "gentler" splits. It's imperative that advanced trainees don't try to move the world in one day. Light day has to remain "light" and with more of an "active recovery" mentality at first, and medium day must be moderate compared to the heavy day (moderate in that substantial weights can be used, but no go-for-broke mentality or trying to tackles PRs - save that for heavy day). Then, after weeks of gradually getting accustomed to this and ramping up slowly the medium day becomes heavier and the light day becomes more "medium" as compared to before. Over time all three days become "hard" but the loading is still heavy/light/medium by definition and PRs are either only attempted on heavy days or on medium days with less stressful exercises or rep maxes instead of maximum weight attempts. (For instance, a conditioned athlete might Bench Press up to a low-rep max set on heavy day and go for a higher-rep/volume PR on Overhead Presses on medium day, say a 5x5 best performance on Overhead Presses or something other than an absolute best for one low-rep set). But unless a person is incredibly gifted, going for some sort of psyched PR on light day, under any circumstance, is asking for trouble. Even the very conditioned would go for something like a best 3x12 on light day with short rest periods - in that case, a maximum light day is more of a strength-endurance PR day than a max-weight-lifted PR day. Ovbviously, the training stimulus is there, but it's achieved in a different manner than on heavy or medium days.
Like anything else, conditioning has to be built gradually just like strength - failing to realize the gravity of that is the biggest mistake advanced trainees usually make when trying something new. Advanced trainees are usually set in their ways to one degree or another, and that can get them into trouble.