Focusing on discourses about high performances in sports and work in Weimar and Nazi Germany, this project aimed at a comprehensive cultural history of the notion of "performance" (Leistung) in German culture, sports, medicine, and psychology from 1914 to 1945. Historians have frequently pointed to sports as a field of activity that was defined in opposition to the work sphere. In early twentieth-century Germany, however, discourses about performances in sports and work informed each other. Far from conceptualizing sport as an antithesis of work, German work physiologists and psychologists talked in terms of sport as a form of work and so did German sport scientists and other observers of sports. The German sports and work sciences were both participants in the rationalization and efficiency debates of the period that centred on Frederick W. Taylor’s system of scientific management. The project, therefore, tried to clarify how discussions about sports performances were related to German debates about efficiency and rationalization. It explored the ways in which sports medicine and psychology contributed to contemporary discussions about sustainable human resource management after the human losses of World War I. Therefore, the project made a contribution to the history of Weimar and Nazi biopolitics understood in a broad sense as attempts to manage and improve the physical and psychological condition of the German population in a systematic manner.