FOREWORD HE tremendous amount of statistical facts gathered for this Loe would not have been possible without the kindly effi- cient cooperation of very many wonderful people. The research is based upon sound established physiological facts. It required severe exhaustive physical efforts and intense prolonged periods of clerical work to correlate those figures. The methods were developed first with the students at the Uni- versity of Pittsburgh. They were confirmed in many nearby Junior and Senior high schools. Later, they were utilized by College and University basketball teams to set up this work. The Aircrew students at Pitt in their conditioning program offered a rare oppor- tunity in nearly perfect controls. Sound technical advice was offered by capable medical men. The actual direction of the tests was done by athletic men, skeptical but efficient in their operations. The clerks handled an infinite number of figures. Without the help in editing, and the advice and execution of illustrations, this work would never have been published. We would like to thank here, by name, everyone who helped, but that would be an impossibility. We trust that the men inadvertently missed will feel that they have helped in a big way to discount some of the superficial and unfounded criticisms of aggressive competitive athletics. Some of the men who conducted these strenuous tests in sec- ondary schools and graciously reported names and figures include the following: Dan Rice of Braddock, Jim Klein of Herron Hill Junior High, Clifford Wells of Logansport, Indiana, Robert Baierl of Munhall, Walter West of Wilmerding, Captain William Palmer and F. Walter Jones of Shadyside Academy. The clerks who handled the statistics of the above tests were former students and basketball players at Pitt and are now in the armed services. They include Captain Mel-*Port, Lt. Edward Strall, Lt. Edwin Masten and Lt. Larry Paffrath. Medical advisers included associate doctors George Kowallis, Howard Bolton, Joseph Staley and Paul Zehfuss of the Men’s Student Health Service at the University of Pittsburgh. Nurses Lorena Dobrick, Ethel Woomer, Jane McConnell and Dolores