Mike Mentzer became famous during the 70's with his ground-breaking method of training called "Heavy Duty". In fact, Mike Menzter's Heavy Duty method was more than a training technique: it is a philosophy of science applied to bodybuilding. Let's not believe however that Mike thought his theory of training was perfect. Even he knew it wasn't: his training schedules changed, as his ability grew to generalize his experience, he consequently changed and corrected his conclusions over the years. It was precisely this point that made Mike Mentzer stand out: he had a continuous interaction with the practical application of his training theory.

Mike Mentzer's theory was and is the only theory on training. In truth, Arthur Jones, the mentor of the young Mike Mentzer, intuitively arrived to a general training theory, however he never applied his findings to a general philosophy of science.

Did Mike Mentzer's theory have limits? Mike based his findings on the writings of Ayn Rand, an economist of the 1930's, and from here he understood correctly that he had to base his results in material reality not on his desires, convictions or what was traditionally believed to true. Rand however was mistaken in her theory, as well as Mentzer, to consider that material reality is always the same, i.e. static, indifferent to human activity. This led Mentzer to make several mistakes: for example he always negated any value to the periodization of training. Despite the errors of Mike Mentzer he founded a theory, that undoubtedly proves, that it is possible to control and transform the human body.