More than 50 years ago, New Zealand's Arthur Lydiard started using terms like base training, periodization, and peaking. His U.S. counterpart, Bill Bowerman, brought Lydiard's term for what until then had been called roadwork, or jogging, to the States. Soon after, the 1970s running boom started, spurred by exercise-advocating research from the growing fields of exercise science and sports medicine and from enthusiasts such as Jim Fixx, author of...