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BACKGROUND AND OBJECTIVES:Regular aerobic and muscle-strengthening physical activity in youth has been positively associated with health and may help prevent obesity. The purpose of this study is to provide reference values on 4 core, upper, and lower body measures of muscle strength among US children and adolescents and to investigate the association between these measures of strength and weight status.METHODS:We assessed muscular strength using 4 different tests (plank, modified pull-up, knee extension, and grip strength) in 1224 youth aged 6 to 15 years collected during the 2012 National Health and Nutrition Examination Survey National Youth Fitness Survey. Mean and median estimates are provided by gender, age, and weight status. Weight status was defined based on standard categories of obesity, overweight, normal weight, and underweight using the gender-specific BMI-for-age Centers for Disease Control and Prevention growth charts.RESULTS:There were significant positive trends with age for each of the strength tests (P < .001) except the modified pull-up among girls. The length of time the plank was held decreased as weight status increased for both girls and boys (P < .001). As weight status increased the number of modified pull-ups decreased (P < .001 boys and girls). Scores on the knee extension increased as weight status increased (P < .01). Grip strength increased as weight status increased (P < .01).CONCLUSIONS:Increasing weight status had a negative association with measures of strength that involved lifting the body, but was associated with improved performances on tests that did not involve lifting the body.

Objectives:To examine trends in preventive asthma medication (PAM) use among children with current asthma in the United States from 1988 to 2008.Methods:We performed a cross-sectional analysis of PAM use among 2499 children aged 1 to 19 years with current asthma using nationally representative data from the National Health and Nutrition Examination Survey (NHANES) during 3 time periods: 1988–1994, 1999–2002, and 2005–2008. PAMs included inhaled corticosteroids, leukotriene receptor antagonists, long-acting β-agonists, mast-cell stabilizers, and methylxanthines.Results:Among children with current asthma, there was an increase in the use of PAMs from 17.8% (SE: 3.3) in 1988–1994 to 34.9% (SE: 3.3) in 2005–2008 (P < .001 for trend). Adjusting for age, gender, race/ethnicity, and health insurance status, the odds of PAM use were higher in 2005–2008 compared with 1988–1994 (adjusted odds ratio [aOR] = 2.6; 95% confidence interval [CI]: 1.5–4.5). A multivariate analysis, combining all 3 time periods, showed lower use of PAMs among non-Hispanic black (aOR = 0.5 [95% CI: 0.4–0.7]) and Mexican American (aOR = 0.6 [95% CI: 0.4–0.9]) children compared to non-Hispanic white children. PAM use was also lower in 12 to 19 year olds compared with 1 to 5 year olds and also in children who did not have health insurance compared with those who did.Conclusions:Between 1988 and 2008, the use of PAM increased among children with current asthma. Non-Hispanic black and Mexican American children, adolescents aged 12 to 19 years, and uninsured children with current asthma had lower use of PAM.