Physical activity guidelines for children and youth This article is part of a supplement entitled Advancing physical activity measurement and guidelines in Canada: a scientific review and evidence-based foundation for the future of Canadian physical activity guidelines co-published by Applied Physiology, Nutrition, and Metabolism and the Canadian Journal of Public Health. It may be cited as Appl Physiol Nutr Metab 32 (Suppl. 2E) or as Can J Public Health 98 (Suppl. 2) - Janssen, I (Appl Physiol Nutr Metab, 2007)