 Context: Sport and physical activity during and after cancer treatment can improve fitness and social inclusion in adults. In children, although early studies show interesting results, conclusive data are lacking. A preliminary evaluation conducted in a dozen children following a physical training program showed a significant improvement in endurance, muscle tone, overall self-esteem, sports skills and self-perceived strength. The investigators then want to evaluate the health of a group of children during treat cancer that physical activities adapted compared to children who did not practice. 