[Trail running: a challenge for medical support teams].

Trail running races are a real challenge for medical and paramedical workers committed to aid station/medical support system, because of their technical and geographical particularities. In this article, we review the different etiologies of collapse, digestive problems, kidney complications, diseases related to the environment and musculoskeletal injuries. Field care and prevention are also examined. Although injuries are often benign, some more serious problems may require rapid and effective intervention. Medical teams must be prepared for each of the different situations discussed in this article.