This article discusses metaphorical views of the body and how they influenced physical exercise practices in France from 1825 to 1935. Until the beginning of the 19th century, the predominant metaphor was of the body as a mechanical structure, a system of levers and pulleys. However, scientific and technological advances – in particular, the development of the combustion engine – led to a change. The new metaphors described the body as an energy-producing machine, comparing it explicitly to a mechanical engine. This led to the promotion of exercise practices that did not just ensure mechanical fitness, but also enhanced the body’s ability to produce energy. This view led to a greater promotion of sports and other “energetic” exercise and the development of the idea of “champion” (someone who has maximized the energy yield of his or her body). The article specifically discusses the views of French scholars Hirn, Marey, Lagrange, Demenij, Hebert, and Tissié, all of whom used the “body-as-machine” metaphor in their writings.