Physical activity by adolescents.
D000203:Activities of Daily Living; D000293:Adolescent; D001823:Body Composition; D001827:Body Height; D001835:Body Weight; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008124:Locomotion; D008297:Male; D009043:Motor Activity; D009747:Nutritional Physiological Phenomena; D010809:Physical Fitness; D011187:Posture; D012923:Social Class