This study questions the forms of coordination between coaches and sport scientists. We focus on too structures of technologies transfer, which are designed to transfer knowledge and technologies from the scientific activity to the field of sport in order to improve performances. The investigations, which consist of observations, interviews and analyse of texts, brought to light that the instrumentations used in the structures of technology transfer are essential supports of the coordination between the actors: they are at the same time dedicated to the production of scientific knowledge and to the training. However, resistances of the trainers to the scientific knowledge happen frequently, and even if the world of sport resorts to science to optimize the training techniques, their coordination is fragile.