To organise the 21st international symposium of the "European Group of Paediatric Exercise Physiology" in Corsendonk, Belgium (September 12-16, 2001). The aim of the group is to promote the international exchange of scientific information relevant to the physiology of exercise in growing individuals. The group consists of physiologists, paediatricians and physical educators. Physical inactivity is an independent risk factor for disease. Physical activity is decreasing in children and adolescents. This will become a major health problem in Europe, particularly in girls. Therefore the title of the 2001 meeting will be "Exercise and Physical (In) activity in Children, with Focus on the Girl". The aim of the meeting is to examine causes of physical inactivity and to formulate guidelines for promoting physical activity in children and adolescents.