The purpose of this essay is to examine the elite sports physician as a medical and moral actor within the world of high-performance sport along with his or her relationship to medical ethics. High-performance sports medicine requires a concept of human nature that enables the medical practitioner to interpret the capacities and limitations of the athlete as a performing organism. This model of human nature enables the physician to administer "treatments" designed to boost athletic performance. At the same time, it should encourage the physician and other observers to think about the ethical limits to this sort of medical behavior. Thinking about human nature is an exercise in philosophical anthropology that can imagine two diametrically opposed interpretations of human limits in relation to athletic performance. A theological doctrine that regards the human being as the product of a Creator will regard the human body as endowed with divinely sanctioned limits that rule out the manipulation of the athletic body by means of drugs or other "doping" techniques. The Vatican has propounded such a doctrine since the 1950s. High-performance sport, in contrast, enlists every human faculty on behalf of producing an optimal athletic performance in defiance of perceived limits. The performance principle [Leistungsprinzip] that animates our technology-based civilization has created an anthropological model of human functioning that presupposes a human organism that must adapt itself, physiologically and psychologically, to the requirements of efficiency and productivity. Performance-enhancement is increasingly a way of life for large numbers of people. Elite athletes represent an extreme subset of this group, and there is a subculture of sports physicians who are willing to administer doping drugs and other unorthodox procedures to promote the repair and enhancement of these extreme performers.