Excerpt and illustrations from Vitality Supreme by Bernarr Macfadden, 1915.
Several years ago I discovered a unique and very effective means of strengthening the heart, lungs, stomach and other internal organs. I arranged a system of lessons, consisting of various pressure movements, which I termed an Inner Strength Course. As my experience with this course had been limited, I refrained at the time from presenting its fundamental theories to the general public. I issued the course in a series of four lessons, and the strength of each applicant was ascertained through questions before the course was sent to him. The experience with several hundred students, however, has so thoroughly confirmed the value of this method of internal vitality building that I am now in a position where I can present the ideas upon which it is based to the general public. The usual price of this course was five dollars, and several thousand courses were sold at this price, each student naturally receiving a certain amount of personal attention.
The same ideas, however, are presented in this chapter, with the warning that those who use the pressure exercises recommended must take care to avoid pressing upon the internal organs beyond their resisting power.