Despite current recommendations against use in adolescents less than 18 years old, creatine is being used by middle and high school athletes at all grade levels. The prevalence in grades 11 and 12 approaches levels reported among collegiate athletes. Until the safety of creatine can be established in adolescents, the use of this product should be discouraged.

The current epidemic of inactivity and the associated epidemic of obesity are being driven by multiple factors (societal, technologic, industrial, commercial, financial) and must be addressed likewise on several fronts. Foremost among these are the expansion of school physical education, dissuading children from pursuing sedentary activities, providing suitable role models for physical activity, and making activity-promoting changes in the environment. This statement outlines ways that pediatric health care providers and public health officials can encourage, monitor, and advocate for increased physical activity for children and teenagers. INTRODUCTION IN 1997, THE World Health Organization declared obesity a global epidemic with major health implications. 1 According to the 1999 -2000 National Health and Nutrition Examination Survey (www.cdc.gov/nchs/nhanes.htm), the prevalence of overweight or obesity in children and youth in the United States is over 15%, a value that has tripled since the 1960s. 2 The health implications of this epidemic are profound. Insulin resistance, type 2 diabetes mellitus, hypertension, obstructive sleep apnea, nonalcoholic steatohepatitis, poor self-esteem, and a lower health-related quality of life are among the comorbidities seen more commonly in affected children and youth than in their unaffected counterparts. [3][4][5][6][7] In addition, up to 80% of obese youth continue this trend into adulthood. 8,9 Adult obesity is associated with higher rates of hypertension, dyslipidemia, and insulin resistance, which are risk factors for coronary artery disease, the leading cause of death in North America. 10 Assessment of OverweightIdeally, methods of measuring body fat should be accurate, inexpensive, and easy to use; have small measurement error; and be well documented with published reference values. Direct measures of body composition, such as underwater weighing, magnetic resonance imaging, computed axial tomography, and dual-energy radiograph absorptiometry, provide an estimate of total body fat mass. These techniques, however, are used mainly in tertiary care centers for research purposes. Anthropometric measures of relative fatness may be inexpensive and easy to use but rely on the skill of the measurer, and their relative accuracy must be validated against a "gold-standard" measure of adiposity. Such indirect methods of www.pediatrics.org/cgi

The effect of 6 months of twice weekly karate training on flexibility, balance, and strength was evaluated in 14 boys who perform karate as beginners (age M = 10.3 ± 1.8) and a group of the same age who had never been involved in martial arts (n = 10; age M = 10.9 ± 1.4). All subjects were pretested and posttested on the following: flexibility of upper extremity (shoulder), hamstrings and quadriceps; strength, including handgrip strength and concentric flexion/extension of quadriceps; and balance, with eyes either open or closed. After 6 months, the tests were evaluated and compared by groups. The results showed the karate group made significant gains on quadriceps flexibility and balance with eyes closed. By improving flexibility, balance, and strength, karate improves three of the basic fitness components that are very important for preventing sport injuries in the growing years.

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We assessed leisure-time Internet use (IU) and its relationship to physical fitness (PF) and leisure-time physical activity (PA) among 295 adolescent African-American girls. In addition, scales measuring variables in the Theory of Reasoned Action (TRA) were administered to elucidate PA data. Based on responses to the IU Questionnaire, participants were placed into either an Internet Nonuser (n = 184) or Internet User (n = 111) group. PF was assessed using body mass index (BMI) and AAHPERD Youth Fitness Tests. There were no correlations found between the fitness test scores and IU, PA, or BMI. No correlation was found between IU and PA, and similar findings were noted between PA and each variable constituting the TRA. As expected, within the TRA variables studied, significant moderate to high correlations were found between both Attitude to Exercise and Subjective Norm with Intention to Exercise, r = .43 and r = .53, respectively. The remarkably low scores among participants on the fitness tests and TRA scales suggest that IU would have no appreciable influence on the PF of this population, irrespective of IU.