"Exercises of speed increase the activity of the respiratory organs with much less fatigue of the lungs and heart than is created by strength exercises, owing to the absence of forced muscular effort. Such effort occurs only accidentally in exercises of speed, but is compulsory in exercises of strength. But exercises of speed will not develop the bulk and strength of muscle as are developed by strength work, for there is a smaller supply of blood forced into the muscles during and after speed work; therefore, the nutrition of the muscle is less active during this kind of work. It is a physiological fact that the nutrition of any part of the body is in direct proportion to the quantity of blood with which it is supplied. But while exercises of speed fall short as developers of muscles, they are much better for the internal organs and they increase the size of the chest and lung capacity - effects of great health importance. Speed work naturally requires more concentration and more power of will in the performance of the movements." - Earle Liederman Visit our website and see our many books at PhysicalCultureBooks.com