SPORT, CAUSE OR CONSEQUENCE?: There are arguments in favour of a "princeps" disorder that would orientate young anorexic girls towards certain sports and exercises, others, conversely, underline the propensity of certain sports to lead to the onset of eating disorders. AN EXAMPLE: The description of a clinical case evokes the complexity of this relationship demonstrating that intensive exercise training may promote such problems but will also limit the severity of anorexia nervosa. FROM A PRACTICAL POINT OF VIEW: We should give up the global concept of "sport" and define "exercise training" the intensity, the exclusiveness and the intrinsic body weight constraints of which are recognised as risk factors, together with a more fragile population (adolescents, females). Based on these data, prevention strategies should be applied in particularly exposed institutions.