Impact of a Physical Activity Program on Bone Mineral Density in Children and Adolescents With Chronic Inflammatory Bowel Disease

Inclusion Criteria: * Patient with IBD (Crohn's disease, ulcerative colitis or unclassified chronic colitis) since at least 6 months. * Computer and internet access at home. * Consent to adhere to a physical activity program. * Assent of the child to participation in the research protocol. * Informed consent of parents or legal guardian. * Patient benefiting from national health. Exclusion Criteria: * At time of inclusion, acute intercurrent events which may lead to a decrease in physical activity (according to the judgment of the investigator) as fractures, recent arthritis, ano-perineal lesions, severe dermatological lesions. * Chronic, acute or intermittent diseases (other than IBD) that may lead to a decrease in physical activity. * Refusal of the child to participate to the protocol. * Refusal of one of the child's parents to participate in the protocol. * Predictable lack of compliance to study procedures (especially to the physical activity program). * Child with visual impairment. * Participation in another interventional study. * Pregnant or lactating women. * Patient under protection of justice.