HOW TO GET STRONG
Gardner Smith, President of the Harlem Medical Association and Physical Director of the Harlem Branch of the Young Men's Christian Association, explains how and why the shape of the chest is thus changed. He says:
"Mechanically, the thorax is a conical box bounded laterally by the ribs; the sternum and costal cartilages anteriorly; the ribs and spinal column posteriorly; the diaphragm, a dome-shaped muscle with a tendinous centre forming the base. This conical box is capable of movement in every direction. Muscles raise the ribs upward and forward, increasing the antero-posterior diameter; muscles rotate the ribs outward and upward and raise them laterally like the bail of a pail; increasing the lateral diameter; the diaphragm moves downward, increasing the vertical diameter.
"The size of the chest thus increased, the air within the lungs becomes rarefied; the pressure within the thorax becomes less, and immediately the external air, with its continual pressure of fifteen pounds to the square inch, rushes in to fill this 'tendency to a vacuum.' Of course it is highly important that the nostrils and other air-passages and the chest and abdominal wall be free from constriction or obstruction."
Again, of these twelve men, in less than eight months every one gained perceptibly in height; indeed, there was an average gain of five-twelfths of an inch in height, though all, save one, were over twenty; and one man who gained half an inch was twenty-eight years old, while one twenty-six gained five-eighths of an inch! (Most people suppose they can get no taller after twenty-one.) All increased decidedly in weight—the smallest gain being 5 pounds, the average 10 pounds; and one, and he twenty-eight, and a five-feet-eleven man, actually went up from 149 pounds at the beginning, to 165 pounds in less than four months. It is not likely there was much fat about them, as they
138
