1. CDC: Physical activity and good nutrition: essential elements to prevent chronic diseases and obesity 2005. 2005,http://www.cdc.gov/nccdphp/aag/aag_dnpa.htm
2. Telama R, Yang X, Laakso L, Viikari J: Physical activity in childhood and adolescence as predictor of physical activity in young adulthood. Am J Prev Med. 1997, 13: 317-323.
3. Centers for Disease Control and Prevention: Physical Activity Levels Among Children Aged 9 – 13 Years – United States, 2002. MMWR Morb Mortal Wkly Rep. 2003, 52 (33): 785-788.
4. Grunbaum JA, Kann L, Kinchen S, Ross J, Hawkins J, Lowry R, Harris WA, McManus T, Chyen D, Collins J: Youth Risk Behavior Surveillance – United States 2003. MMWR CDC Surveill Summ. 2004, 53 (SS02): 1-96.
5. U.S. Department of Health and Human Services: Physical Activity and Health: A Report of the Surgeon General. 1996, Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Chronic Disease Prevention and Health Promotion