In order to be capable to participate in complex practical settings, sports' actors obviously have to run through long processes of training in which they develop, reshape and refine (sport-)specific forms of knowledge and skills in continuous exercise. At the same time, the question how competent athletes precisely develop these forms of knowledge and skills remains mostly unanswered in sports sciences in general and in the sociology of sports in particular. With reference to practice and subject theories from social sciences and cultural studies, interdisciplinary concepts of knowledge and by means of the application of ethnographic methodology, I intend to fill this desideratum theoretically and empirically. The development of competent athletes takes place in collective, publicly observable practices, which spread across the actions of individual actors; practices, which are organised and held together by a supra-individual knowing-how that exists only within the bodily execution of these practices. To the extend in which actors become involved as practices' participants, they partake in its specific knowledge and embody it. In the actors' phenomenal experience, the practical knowledge expresses itself as some sort of corporal sensation, feel or “sense of the game” (Bourdieu) and guarantees not only the generation of routinised practices, but also allows to creatively modulate practices in unexpected situations and – in the interplay with their co-actors – to apprehend and flexibly realise potentials of actions embedded in situations. Through participation in a given practice, subjects are shaped who acquire practice-specific stocks of knowledge as well as practice-specific ways of feeling, experiencing and thinking based on which they keep the practice going. Ethnographic methods are particularly suited for empirical analyses of sportive practices and processes of subjectivation: Via observations of training processes in vivo and qualitative interviews, the PhD-project aims to disclose how athletes ensure their practice's success collectively, which forms of knowledge, feeling and sensation become effective and how these forms become incorporated and embodied within collective practices of training.