In 1876 the renowned American long-distance pedestrian Edward Payson Weston travelled to Britain to challenge local sportsmen and to raise his transatlantic sporting profile. In February, wearing his distinctive athletic outfit of knickerbockers, leather leggings and walking boots that 'reach [ed] above the ankle', he attempted a walk of 115 miles in twenty-four hours around a track in the Royal Agricultural Hall in Islington, London. 1 This race is relatively well known in the history of sport, used to demonstrate increasing internationalism, or perhaps increasing professionalization, in sport, both taken as symptoms of modernity. 2 My argument is that Weston's walk should be allowed to intrude on other histories too: he was part of an international debate about science, and a national debate about the relationship between the state and its citizens, which embroiled chemists, physiologists, physicists, doctors and social reformers for years. This iteration of the debate had been sparked in earnest a little over a decade earlier, in 1865, when two German researchers climbed the Faulhorn, one of a ring of mountains in the Bernese Alps, eating only fried starch paste, drinking only sugary tea and meticulously collecting their urine. 3 Following the path from the Faulhorn to the Royal Agricultural Hall leads us through the first encounters between modern sports * Research for this article was funded in part by the Wellcome Trust (grant no. 088204/Z/09/A) and the Isaac Newton Trust. Writing up was made possible by the