Interdisciplinarity is often presented as a significant element of sport science. We present here the results of an investigation conducted in four European Sport Science Research Centres applying interdisciplinarity. Four main dimensions, that we have called "forms", have been investigated. The "scientific", "organisational", "academic" and "societal" forms cover a wide range of activities run by these Centres. We have compared their situations using indicators. Globally they present quite similar combinations of forms, with dominant roles in the construction of interdisciplinarity played by the organisational and societal forms. The scientific form is never quite supported by an epistemological setting and the academic form, mostly characterised by the position of the university, plays an influential role when it is hostile to that kind of research. Following Klein classification, all of them remain at a multidisciplinary stage, one of them exploring interdisciplinary tracks in some research projects. The development of a common culture and a curiosity regarding disciplines other than its own is a key factor for a sustainable situation, as is the capacity to secure long-term financial resources, often linked to a high academic recognition for the director(s).