Estimating body composition in adolescent sprint athletes : comparison of different methods in a 3 years longitudinal design

A recommended field method to assess body composition in adolescent sprint athletes is currently lacking. Existing methods developed for non-athletic adolescents were not longitudinally validated and do not take maturation status into account. This longitudinal study compared two field methods, i.e., a Bio Impedance Analysis (BIA) and a skinfold based equation, with underwater densitometry to track body fat percentage relative to years from age at peak height velocity in adolescent sprint athletes. In this study, adolescent sprint athletes (34 girls, 35 boys) were measured every 6 months during 3 years (age at start = 14.8 +/- 1.5yrs in girls and 14.7 +/- 1.9yrs in boys). Body fat percentage was estimated in 3 different ways: 1) using BIA with the TANITA TBF 410; 2) using a skinfold based equation; 3) using underwater densitometry which was considered as the reference method. Height for age since birth was used to estimate age at peak height velocity. Cross-sectional analyses were performed using repeated measures ANOVA and Pearson correlations between measurement methods at each occasion. Data were analyzed longitudinally using a multilevel cross-classified model with the PROC Mixed procedure. In boys, compared to underwater densitometry, the skinfold based formula revealed comparable values for body fatness during the study period whereas BIA showed a different pattern leading to an overestimation of body fatness starting from 4 years after age at peak height velocity. In girls, both the skinfold based formula and BIA overestimated body fatness across the whole range of years from peak height velocity. The skinfold based method appears to give an acceptable estimation of body composition during growth as compared to underwater densitometry in male adolescent sprinters. In girls, caution is warranted when interpreting estimations of body fatness by both BIA and a skinfold based formula since both methods tend to give an overestimation

Percentile reference values for anthropometric body composition indices in European children from the IDEFICS study

INTRODUCTION: To characterise the nutritional status in children with obesity or wasting conditions, European anthropometric reference values for body composition measures beyond the body mass index (BMI) are needed. Differentiated assessment of body composition in children has long been hampered by the lack of appropriate references. OBJECTIVES: The aim of our study is to provide percentiles for body composition indices in normal weight European children, based on the IDEFICS cohort (Identification and prevention of Dietary-and lifestyle-induced health Effects in Children and infantS). METHODS: Overall 18 745 2.0-10.9-year-old children from eight countries participated in the study. Children classified as overweight/obese or underweight according to IOTF (N = 5915) were excluded from the analysis. Anthropometric measurements (BMI (N = 12 830); triceps, subscapular, fat mass and fat mass index (N = 11 845-11 901); biceps, suprailiac skinfolds, sum of skinfolds calculated from skinfold thicknesses (N = 8129-8205), neck circumference (N = 12 241); waist circumference and waist-to-height ratio (N = 12 381)) were analysed stratified by sex and smoothed 1st, 3rd, 10th, 25th, 50th, 75th, 90th, 97th and 99th percentile curves were calculated using GAMLSS. RESULTS: Percentile values of the most important anthropometric measures related to the degree of adiposity are depicted for European girls and boys. Age-and sex-specific differences were investigated for all measures. As an example, the 50th and 99th percentile values of waist circumference ranged from 50.7-59.2 cm and from 51.3-58.7 cm in 4.5-to < 5.0-year-old girls and boys, respectively, to 60.6-74.5 cm in girls and to 59.9-76.7 cm in boys at the age of 10.5-10.9 years. CONCLUSION: The presented percentile curves may aid a differentiated assessment of total and abdominal adiposity in European children

Independent associations of physical activity and cardiorespiratory fitness with metabolic risk factors in children: the European youth heart study

Udgivelsesdato: septemberAIMS/HYPOTHESIS: High levels of cardiorespiratory fitness (CRF) and physical activity (PA) are associated with a favourable metabolic risk profile. However, there has been no thorough exploration of the independent contributions of cardiorespiratory fitness and subcomponents of activity (total PA, time spent sedentary, and time spent in light, moderate and vigorous intensity PA) to metabolic risk factors in children and the relative importance of these factors. METHODS: We performed a population-based, cross-sectional study in 9- to 10- and 15- to 16-year-old boys and girls from three regions of Europe (n = 1709). We examined the independent associations of subcomponents of PA and CRF with metabolic risk factors (waist circumference, BP, fasting glucose, insulin, triacylglycerol and HDL-cholesterol levels). Clustered metabolic risk was expressed as a continuously distributed score calculated as the average of the standardised values of the six subcomponents. RESULTS: CRF (standardised beta = -0.09, 95% CI -0.12, -0.06), total PA (standardised beta = -0.08, 95% CI -0.10, -0.05) and all other subcomponents of PA were significantly associated with clustered metabolic risk. After excluding waist circumference from the summary score and further adjustment for waist circumference as a confounding factor, the magnitude of the association between CRF and clustered metabolic risk was attenuated (standardised beta = -0.05, 95% CI -0.08, -0.02), whereas the association with total PA was unchanged (standardised beta = -0.08 95% CI -0.10, -0.05). CONCLUSIONS/INTERPRETATION: PA and CRF are separately and independently associated with individual and clustered metabolic risk factors in children. The association between CRF and clustered risk is partly mediated or confounded by adiposity, whereas the association between activity and clustered risk is independent of adiposity. Our results suggest that fitness and activity affect metabolic risk through different pathways

The Eyes Have It: Sex and Sexual Orientation Differences in Pupil Dilation Patterns

Recent research suggests profound sex and sexual orientation differences in sexual response. These results, however, are based on measures of genital arousal, which have potential limitations such as volunteer bias and differential measures for the sexes. The present study introduces a measure less affected by these limitations. We assessed the pupil dilation of 325 men and women of various sexual orientations to male and female erotic stimuli. Results supported hypotheses. In general, self-reported sexual orientation corresponded with pupil dilation to men and women. Among men, substantial dilation to both sexes was most common in bisexual-identified men. In contrast, among women, substantial dilation to both sexes was most common in heterosexual-identified women. Possible reasons for these differences are discussed. Because the measure of pupil dilation is less invasive than previous measures of sexual response, it allows for studying diverse age and cultural populations, usually not included in sexuality research

Chronic hypothermia and energy expenditure in a neurodevelopmentally disabled patient: a case study

Hypothermia is defined as a core body temperature of \u3c35°C and results in a decrease in measured resting energy expenditure. A 51-year-old mentally disabled patient experienced chronic hypothermia from neurologic sequelae. Because of her continued weight gain and increased body fat in the presence of presumed hypocaloric nutrition, indirect calorimetry measurements were performed twice in a 3-month period. The resting energy expenditure measurements prompted a reduction of her daily caloric intake to prevent further overfeeding. Hypothermia reduces oxygen consumption and, as a consequence, decreases resting energy expenditure. In patients for whom chronic hypothermia is a problem, nutritional intake must be adjusted to prevent overfeeding, excessive weight gain, and the long-term complications of an excess of total calories

Relationships between overweight, obesity and physical fitness of nine- to twelve-year-old South African children

Background: South African children show the same tendencies in overweight and obesity as children in developed countries a decade ago. Childhood overweight is associated with chronic diseases, early mortality in adulthood and psycho-social effects with lifelong consequences. This study aimed to determine relationships between overweight, obesity and physical fitness of nine- to twelve-year-old South African children. Methods: Anthropometric (body-mass index [BMI], fat percentage) and physical fitness (cardiovascular endurance, body composition, muscle strength, muscle endurance, flexibility) measurements were obtained from 280 children aged nine to twelve years (128 boys, 152 girls) using the Fitnessgram and Bruininks-Oseretsky Test of Motor Proficiency II. International cut-off points were used to categorise children into normal-weight, overweight or obese categories. Data were analysed using descriptive statistics, Spearman rank order correlation and variance of analysis. Results: One in five children was overweight or obese, while girls were twice as likely as boys to be obese. Aerobic capacity and muscle strength, especially leg strength, decreased progressively with an increase in BMI. A progressive but nonsignificant decline was found in muscle endurance with increasing BMI, while flexibility showed the poorest relationships with various degrees of weight. Variance of analysis indicated significant relationships between BMI, cardiovascular endurance and strength (p < 0.05), while different relationships were found when gender was taken into consideration. Conclusions: Health-enhancing physical fitness of young children is negatively affected by overweight and obesity, and intervention strategies are recommended to improve the quality of life of such childre,n but also to prevent early mortality during adulthood.Keywords: overweight; obesity; children; gender; physical fitnes

Longitudinal investigation of training status and cardiopulmonary responses in pre- and early-pubertal children

PurposeThe presence of a maturational threshold that modulates children’s physiological responses to exercise training continues to be debated, not least due to a lack of longitudinal evidence to address this question. The purpose of this study was to investigate the interaction between swim-training status and maturity in nineteen trained (T, 10 ± 1 years, −2.4 ± 1.9 years pre-peak height velocity, 8 boys) and fifteen untrained (UT, 10 ± 1 years, −2.3 ± 0.9 years pre-peak height velocity, 5 boys) children, at three annual measurements.MethodsIn addition to pulmonary gas exchange measurements, stroke volume (SV) and cardiac output ( Q˙) were estimated by thoracic bioelectrical impedance during incremental ramp exercise.ResultsAt baseline and both subsequent measurement points, trained children had significantly (P &#60; 0.05) higher peak oxygen uptake (year 1 T 1.75 ± 0.34 vs. UT 1.49 ± 0.22; year 2 T 2.01 ± 0.31 vs. UT 1.65 ± 0.08; year 3 T 2.07 ± 0.30 vs. UT 1.77 ± 0.16 l min−1) and Q˙ (year 1 T 15.0 ± 2.9 vs. UT 13.2 ± 2.2; year 2 T 16.1 ± 2.8 vs. UT 13.8 ± 2.9; year 3 T 19.3 ± 4.4 vs. UT 16.0 ± 2.7 l min−1). Furthermore, the SV response pattern differed significantly with training status, demonstrating the conventional plateau in UT but a progressive increase in T. Multilevel modelling revealed that none of the measured pulmonary or cardiovascular parameters interacted with maturational status, and the magnitude of the difference between T and UT was similar, irrespective of maturational status.ConclusionThe results of this novel longitudinal study challenge the notion that differences in training status in young people are only evident once a maturational threshold has been exceeded

Anthropometry and body composition in ethnic Japanese and Caucasian adolescent girls: Considerations on ethnicity and menarche

Objective: This study aimed to compare the various anthropometric and body composition parameters based on the ethnicity and the absence or presence of menarche.Design: A cross-sectional study with incomplete sampling, using the subject as the evaluation unit.Subjects: the final sample of 550 subjects was composed of 122 Japanese and 179 Caucasian premenarcheal adolescents, and 72 Japanese and 177 Caucasian postmenarcheal adolescents.Methods: the variables of body composition were measured through the following methods: bioelectrical impedance analysis, near-infrared interactance (NIR), Slaughter cutaneous skinfold equations and body mass index. Weight, height and sitting height were also evaluated.Results: the Japanese pre- and postmenarcheal girls presented lower weight and height values when compared with the Caucasian girls. in general, the Japanese premenarcheal girls presented less fat and fat-free mass than the premenarcheal Caucasian girls. This fact was demonstrated through NIR results. Conversely, the Japanese postmenarcheal adolescents accumulated more fat than their Caucasian counterparts. However, significant differences were solely encountered in the values of cutaneous skinfold percent body fat. With regard to menarche, it was verified that, regardless of ethnicity, all the anthropometric and body composition variables reached higher values among postmenarcheal adolescents when compared with premenarcheal adolescents.Conclusion: Different results of weight and height between the ethnic groups may bring back the discussion concerning separate growth curves for different ethnic groups. the results of the body composition analysis indicated high adiposity levels among postmenarcheal adolescents.Universidade Federal de São Paulo, Escola Paulista Med, Dept Postgrad Nutr, BR-04020060 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Prevent Med, São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Postgrad Nutr, BR-04020060 São Paulo, BrazilUniversidade Federal de São Paulo, Escola Paulista Med, Dept Prevent Med, São Paulo, BrazilWeb of Scienc

Combined Tevatron upper limit on gg->H->W+W- and constraints on the Higgs boson mass in fourth-generation fermion models

Report number: FERMILAB-PUB-10-125-EWe combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg->H->W+W- in p=pbar collisions at the Fermilab Tevatron Collider at sqrt{s}=1.96 TeV. With 4.8 fb-1 of integrated luminosity analyzed at CDF and 5.4 fb-1 at D0, the 95% Confidence Level upper limit on \sigma(gg->H) x B(H->W+W-) is 1.75 pb at m_H=120 GeV, 0.38 pb at m_H=165 GeV, and 0.83 pb at m_H=200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% Confidence Level a standard-model-like Higgs boson with a mass between 131 and 204 GeV.We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg→H→W+W- in pp̅ collisions at the Fermilab Tevatron Collider at √s=1.96  TeV. With 4.8  fb-1 of integrated luminosity analyzed at CDF and 5.4  fb-1 at D0, the 95% confidence level upper limit on σ(gg→H)×B(H→W+W-) is 1.75 pb at mH=120  GeV, 0.38 pb at mH=165  GeV, and 0.83 pb at mH=200  GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, we exclude at the 95% confidence level a standard-model-like Higgs boson with a mass between 131 and 204 GeV.Peer reviewe