here's an interview with Mentzer where he talks about how he would have trained back when he was competing after he made his "latest discoveries"
1. Q. I have read many articles of yours and you always advise bodybuilders that they should train with high intensity, once every 5 - 7 days, and every training session should not last more than 20 minutes in order to achieve maximum muscle stimulation. My question to you is, if 20 years ago you had the knowledge that you have today, would you train with the same frequency and duration for a bodybuilding competition or might you change something?
M.M. Given the knowledge I have today, I certainly wouldn′t train in the same fashion I did 20 years ago. In fact, I wrote in my book "Heavy Duty I, "Despite having been the arch-advocate of lesser training [20 years ago] I, too, was still overtaining." What I have learned over the last 11 years, since taking up personal training, is that weight resistance is much, much more stressful than the average bodybuilder might fathom.
Lifting weights places stresses on the body that might be best illustrated by the following. Imagine a flat, horizontal line drawn on a piece of paper from left to right,with the flat line representing zero effort. Now imagine a squiggly sine wave come off the zero effort flat line, the sine wave representing efforts of various sorts. You get out of bed each morning, shower, brush your teeth, walk to your car, drive to work and so forth.
These are small efforts causing the sine wave to barely move above the flat line.
Then, all of a sudden, you come to that point in the day where you do a heavy set of Squats to failure. All of a sudden the sine wave departs straight up off the paper and across the street! The distance from the flat line to the apex of that spike represents not only the greater intensity with the Squats but, also, the much greater inroad into recovery ability than our usual, daily little efforts.
I wrote in my book "Heavy Duty II: Mind and Body" that the idea is not "more is better" or "less is better" but "precise is best"; and as I learned from training close to 2,000 people plus myself that the precise amount of exercise required to induce optimal growth stimulation isn′t nearly as much as you′ve been led to believe or would like to believe.
Remember, the idea is not to go into the gym to discover how many sets you can do or how long you can mindlessly endure. Instead, the idea is to go into the gym as an informed, rational individual and do only the precise amount of exercise required to stimulate growth and no more; then get the hell out of the gym, go home and GROW! A bodybuilding workout, by God, is not an endurance contest!
Last year I was in 80 percent of my shape, and my leg workouts lasted six minutes and upper body workouts 15 minutes, training once every four to seven days.