If there was a physical activity that caught on during the last few decades of the twentieth century, it was jogging. Running and sprinting had been around since time immemorial and were associated with competitive running. Jogging, on the other hand, achieved currency when individuals took up the deliberately paced trotting as part of fitness regimes. At some point, when the briskness or doggedness of noncompetitive jogging reached a certain level, the more impressive word "running" came to be more or less interchangeable with "jogging."

James (Jim) Fixx was an important figure on the cusp of the jogging boom. In 1977, Fixx triggered a revolution in physical activity with his book The Complete Book of Running. He made getting out of bed early to put on sweat clothes and sneakers the stylish thing to do. Panting and sweating became fashionable. Although Fixx popularized the movement, years earlier Dr. Kenneth...