The Age of Fitness

We live in the age of fitness. Hundreds of thousands of people run marathons and millions go jogging in local parks, work out in gyms, cycle, swim, or practice yoga. The vast majority are not engaged in competitive sport and are not trying to win any medals. They just want to get fit. Why this modern preoccupation with fitness?

In this new book, Jürgen Martschukat traces the roots of our...