In combat sports with weight categories, competitors have the obligation to “make the weight” of their category, at the time of the official weigh-in before each competition. The thesis aims to understand weight control practices among high-level judokas and judokas. She is interested in the daily experience of athletes, the mode of dissemination of practices and knowledge and their evolution in a world where the quest for performance is a permanent issue. The interactionist approach is located at the interface of the sociology of sport, the sociology of health and the sociology of risk. The concepts of “career” and “trajectory” are used to understand the construction of weight control practices in the judoka’s career and their evolution in their own trajectory. The qualitative approach is based on an ethnographic survey lasting 230 days carried out in around ten countries during preparatory courses and international competitions. It was supplemented by 48 “life stories” carried out with 21 women and 27 men aged 18 to 41, high-level athletes. The process of constructing weight control practices is captured in the context of careers, making it possible to account for both objective facts relating to the sporting structure, as well as changes in the knowledge, conceptions and desires of athletes. Weight control practices, the foundations of which are generally built at the end of adolescence, develop along a trajectory that tends to become independent of the judoka career. The analysis highlights situations of vulnerability both in the sporting career and within the trajectory itself
