check out this testimonial from mike's website (especially check out what i've underlinded!):
HEAVY DUTY DOES INDEED WORK! -- Posted 2/8/06
Mark Martinez – Track and Field Coach - Santa Fe, New Mexico - USA
Back in the early to mid-‘90s, after several years of inactivity, I began working out again in my quest for size and power. I tried many different methods of training, from training once a day, to two and three times a day. I tried the Bulgarian method of training and believe it or not, I even tried Power Factor Training. Sometime afterwards, I remembered about a bodybuilder that I would see in the muscle magazines - the bodybuilder was MIKE MENTZER. I recall how impressed I was when looking at the pictures of him and his brother working out, and how much effort they seemed to be putting into their workouts. I began searching the magazines to see if I could find anything about Mike Mentzer regarding his workout routine. It took some time, but I found an article where he gave an update on himself and said that he was doing personal training and phone consultations.
I guess at this point Mike had started writing for one of the magazines, and I couldn’t believe what I was reading. It made sense and he didn’t dumb it down. I found that he wrote the way he spoke - articulate and to the point. After using his routine that I got out of the magazine article, I started making pretty good gains! I finally realized that if I wanted to continue my quest for more size and strength, then I would have to call Mike and purchase some consultations. I ended up purchasing a total of ten (I believe) phone consultations from Mike. On the day I purchased them, Mike got some general information from me regarding what I did for a living, what I was doing for workouts, how often and so forth.
I finally called Mike a few weeks later for my first session. Mike spoke about how bodybuilding is a science, that you need rest, etc. (it is all in his books and other writings). The one thing I distinctly remember is Mike saying that he had it perfected. I took notes on everything he said that day. Finally the moment that I was waiting for came, the workout. I was told to do 1 set of Pec Deck with Inclines on a smith machine in superset fashion, lower the bar to my neck with my elbows flared back towards my ears (really involved my pecs doing it this way, awesome), etc. I recall that when Mike told me how many rest days to take between workouts, “workout once every four days”, I balked “every four days”? He probably started laughing inside, but then he again explained to me the importance of rest and assured me this was what was necessary.