Search

The emergence of obesity, insulin resistance, and type 2 diabetes in children requires a rational, effective public health response. Physical activity remains an important component of prevention and treatment for obesity, type 2 diabetes, and insulin resistance. Studies in adults show cardiovascular fitness to be more important than obesity in predicting insulin resistance. We recently demonstrated that a school-based fitness intervention in children who are overweight could improve cardiovascular fitness, body composition, and insulin sensitivity (5), but it remains unclear whether accurate assessment of fitness could be performed at the school or outside of an exercise laboratory. To determine whether new methodology using measurement of cycling power could estimate cardiovascular aerobic fitness (as defined by [Vo.sub.2max]) in middle school children who were overweight. Thirty-five middle school children (mean age 12 [+ or -] 0.4 years) who were overweight underwent testing on a power sensor-equipped Cycle Ops[R] indoor cycle (Saris Cycling Group, Fitchburg, WI) as well as body composition by dual x-ray absorptiometry and [Vo.sub.2max] by treadmill determination. Insulin sensitivity was also estimated by fasting glucose and insulin. Maximal heart rate (MHR) was determined during [Vo.sub.2max] testing, and power produced at 80% MHR was recorded. Spearman's rank correlation was performed to evaluate associations. Mean power determined on the indoor cycle at 80% of MHR was 129 [+ or -] 77 watts, and average power at 80% MHR divided by total body weight was 1.5 [+ or -] 0.5. A significant correlation between watts and total body weight was seen for [Vo.sub.2max] (P = 0.03), and significant negative correlation was seen between watts/total body weight and fasting insulin (P < 0.05). Among middle school children who were overweight, there was a significant relationship between the power component of fitness and cardiovascular aerobic fitness (measured by [Vo.sub.2max]), This more accessible and less intimidating field-based measure of power may prove useful in predicting changes in cardiovascular fitness. Thus, accurate assessment of childhood aerobic fitness may be achievable by measurement of power, possibly within the school environment, at substantially less cost and effort than laboratory-based measurements. KEY WORDS bicycling, obesity, [Vo.sub.2max]

Background: The body mass index (BMI) is a simple and widely utilized screening tool for obesity in children and adults. The purpose of this investigation was to evaluate if BMI could predict total fat mass (TFM) and percent body fat (%FAT) in a sample of overweight and obese children.Methods: In this observational study, body composition was measured by dual energy x-ray absorptiometry (DXA) in 663 male and female overweight and obese children at baseline within a multidisciplinary, pediatric fitness clinic at an academic medical center. Univariate and multivariate regression analyses were conducted to evaluate whether BMI z-score (BMIz) predicts TFM or %FAT.Results: The BMIz, sex and age of subjects were identified as significant predictors for both TFM and %FAT. In subjects younger than 9 years, the BMIz was a weak to moderate predictor for both TFM (R2 = 0.03 for males and 0.26 for females) and %FAT (R2 = 0.22 for males and 0.38 for females). For subjects between 9 and 18 years, the BMIz was a strong predictor for TFM (R2 between 0.57 and 0.73) while BMIz remained only moderately predictive for %FAT (R2 between 0.22 and 0.42).Conclusions: These findings advance the understanding of the utility and limitations of BMI in children and adolescents. In youth (9-18y), BMIz is a strong predictor for TFM, but a weaker predictor of relative body fat (%FAT). In children younger than 9y, BMIz is only a weak to moderate predictor for both TFM and %FAT. This study cautions the use of BMIz as a predictor of %FAT in children younger than 9 years. [ABSTRACT FROM AUTHOR]

The article discusses a study on the effectiveness of a school-based fitness program in improving the health of non-obese children. Factors that were evaluated include cardiovascular fitness (CVF), body composition, insulin sensitivity and markets of inflammation such as adinopectin. The study found that obese and non-obese patients could benefit from fitness programs in school.

Objective: To demonstrate the ability of a submaximal test to predict V̇O2max in overweight children. Study design: A total of 130 children, 11 to 14 years old, with body mass index >85 percentile for age and sex performed a submaximal walking test. V̇O2max was measured by using open circuit spirometry during a graded exercise test to volitional fatigue. An equation to predict V̇O2max was modeled by using the variables of sex, weight (kg), height (cm), heart rate (HR) after 4 minutes during the submaximal test (4minHR), HR difference (4minHR − resting HR), and submaximal treadmill speed (miles per hour [mph]) in 75% of the subjects. Validation was performed by using the remaining 25% of subjects. Results: A total of 113 subjects achieved a maximal effort and was used in the statistical analysis. Development and validation groups were similar in all aspects. On validation, the mean square error was 241.06 with the predicted V̇O2max within 10% of the observed value in 67% of subjects. Conclusion: V̇O2max was accurately predicted in this cohort of overweight children by using a submaximal, treadmill-based testing protocol. [Copyright &y& Elsevier]

Reduced cardiovascular fitness (CVF) is a risk factor for obesity and cardiovascular disease. It has previously shown that a school-based fitness curriculum can improve CVF, and other health indicators in middle school aged children. Whether an afterschool program improves CVF and other health markers in elementary-school children is unresolved. The objective of this study was therefore to determine whether an on-site afterschool-based fitness program improves body composition, cardiovascular fitness level, in elementary school children. 80 elementary school children were evaluated in a "fitness-oriented" afterschool program managed by the local YMCA. Children underwent evaluation of cardiovascular fitness by maximal VO 2 treadmill testing and body composition by dual x-ray absorptiometry (DXA), at baseline (prior to the school-year) and again at end of the school year. Findings revealed that, at baseline, children had a mean age of 8.8 years, BMI of 18.7± 3, with a maximal VO 2 of 40.03 ± 7.6 ml/kg/min, and percent body fat of 28.7 ± 7%. After a 9-month intervention, children maximal VO 2 increased to 44.8 ± 7.5 ml/kg/min (p=0.04) and percent body fat decreased to 25.8 ± 6.2% (p=0.033). The study concluded that on-site afterschool programming focusing on fitness improved body composition and cardiovascular fitness, in elementary school children. Combined with prior studies, these data demonstrate that afterschool-based fitness curricula can benefit both obese and non-obese children. It was therefore recommended that, partnerships with schools to promote fitness even outside of school time should be a part of a school approach to improving children's health.