Interpretation of peak oxygen consumption in 10–12-year-old soccer players: effect of biological maturation and body size

The aim of this study was to investigate the effect of biological maturation and body size on aerobic capacity using appropriate scaling procedures in 10–12-year-old soccer players divided into late, average and early maturing boys. Peak oxygen consumption (VO2peak) was expressed as absolute values, ratio standards, theoretical exponents and experimentally observed exponents. VO2peak was not directly proportional to body mass as the experimentally observed exponent for body mass calculated through linear regression analysis yielded to b=0.64 (R2=0.62; p2peak expressed in l/min was different (p2peak values were adjusted for body mass (ml/min/kg), or when the effect of body mass was adjusted for using theoretical exponent scales (ml/kg0.67/min, ml/kg0.75/min) and experimentally observed exponent (ml/kg0.64/min), the VO2peak responses displayed relativeley constant values (p>0.05) throughout different maturation groups. Linear regression analyses indicated that after adjusting for the effects of body mass using the theoretical exponent scales (ml/min/kg0.67), biological maturation and body size had no effect on VO2peak values in young soccer players. In conclusion, the theoretical exponent scale for body mass (ml/kg0.67/min) control adequately for biological maturation and body size differences in VO2peak in 10–12-year-old soccer players. Therefore, more mature soccer players with better body size values should not be preferentially selected for young soccer teams

Bone mineral density and hormonal status in adolescent athletic girls

The aim of this study was to determine the relationships of bone mineral density (BMD) and content (BMC) with selected fasting hormones in adolescents with different exercise training patterns. The participants were female athletes of weight-loaded (n=23) and weight-supported (n=24) sports, and 33 non-athletic girls aged 13–15 years. BMD (g/cm2) and BMC (g) at the femoral neck (FN) and lumbar spine (LS) were measured. Venous blood samples were drawn to determine the concentration of insulin-like growth factor-1 (IGF-1), IGF binding protein-3 (IGFBP-3), estradiol, visfatin, adiponectin, leptin, insulin, and glucose. After adjusting for age, height, and body mass, the relationships of BMD variables with IGF-1, IGF-1/IGFBP-3 molar ratio, estradiol, and leptin levels remained significant only in the weight-loaded sport group (r=0.41–0.60; p<0.05). Adiponectin was inversely correlated to FN and LS BMD and BMC (r=–0.47–0.62; p<0.05) in weight-supported sport group only, but after adjustments for age, height, and body mass, these associations disappeared. In this study, concentrations of visfatin, a fairly new adipocytokine, were not related to bone parameters in adolescent girls with different training patterns

Relationships between Anthropometric, Body Composition and Bone Mineral Parameters in 7-8-year-old Rhythmic Gymnasts Compared with Controls

The aim of the study was to investigate the relationships between specific anthropometric (9 skinfolds, 13 girths, 8 lengths and 8 breadths), body composition (body fat %, fat free mass [FFM], fatmass [FM]) parameters and bone mineral parameters (bone mineral density [BMD], bone mineral content [BMC]) in young rhythmic gymnasts and same age controls. Eighty nine 7-8-year-old girls participated in this study and were divided to the rhythmic gymnast\u27s (n=46) and control (n=43) groups. Body composition was determined by dual energy X-ray absorptiometry (FFM, FM, body fat %, BMD and BMC). Body fat % and FM were lower and BMD and BMC values at lumbar spine (L2-L4) and femoral neck were higher in rhythmic gymnasts compared with controls. All measured skinfold thicknesses were thicker in controls. In girths, lengths and widths there were only few significant differences between the groups. Stepwise multiple regression analysis indicated that skinfold thicknesses (supraspinale and medial calf) influenced L2-L4 BMD only in controls 38.2% (R2x100). Supraspinale and iliac crest skinfold thicknesses characterised L2-L4 BMC 43.9% (R2x100). Calf girths influenced BMD in L2-L4 52.3% (R²x100) in controls. BMC in L2-L4 was dependent only on mid-thigh girths 35.9% (R2x100). BMD in L2-L4 was dependent on tibiale-laterale height 30.0% (R2x100). Biiliocristal breadths together with sitting height characterised BMC in L2-L4 BMD 62.3% (R2x100). In conclusion, we found that the relationships between anthropometry, body composition and bone parameters in young rhythmic gymnasts are weak. In control group first of all lower body anthropometric parameters significantly correlated with BMD and BMC in spine

Caliper vs. Lipometer - comparing two methods of subcutaneous body fat measurement by Bland-Altman diagrams

Skinfold Calipers are widely used to obtain subcutaneous adipose tissue thickness because of its non-invasive, simple and inexpensive technique. Nevertheless, Caliper skinfold thicknesses have the disadvantage of measuring compressed adipose tissue and double layers of skin, which might reduce the precision of these results. In contrast, the computerized optical device Lipometer was developed to permit a quick, precise and non-invasive determination of non-compressed mono layers of subcutaneous adipose tissue thickness. In the present paper we investigate the hypothesis that Caliper skinfold thicknesses are significantly different from subcutaneous adipose tissue thicknesses in mm, which can be measured by Lipometer. Caliper and Lipometer results were obtained from 371 Estonian boys aged between 9.0 and 12.8 years. Measurements were performed at six different body sites: triceps, biceps, upper back, upper abdomen, hip and front thigh. Caliper measurements were systematically higher than Lipometer results in a range between 1.2 mm (hip) and 11.08 mm (front thigh). Comparing Caliper and Lipometer results very low measurement agreement was found. The two methods provided very poor interchangeability

Normal Weight Estonian Prepubertal Boys Show a More Cardiovascular-Risk-Associated Adipose Tissue Distribution than Austrian Counterparts

Objective. Risk phenotypes for cardiovascular disease (CVD) differ markedly between countries, like the reported high difference in CVD mortality in Austria and Estonia. Hitherto, the goal of this study was to find out risk profiles in body fat distribution yet present in childhood, paving the way for later clinical end points. Methods. he subcutaneous adipose tissue (SAT) distribution patterns in 553 Austrian (A) and Estonian (E) clinically healthy normal weight boys aged 11.1 (±0.8) years were analysed. We applied the patented optical device Lipometer which determines the individual subcutaneous adipose tissue topography (SAT-Top). Results. Total body fat did not differ significantly between E and A boys. A discriminant analysis using all Lipometer data, BMI, and the total body fat (TBF) yielded 84.6% of the boys correctly classified in Estonians and Austrians by 9 body sites. A factor analysis identified the SAT distribution of E as critically similar to male adult patients with coronary heart disease (CHD). Conclusions. We show in normal weight Estonian boys a highly significant decreased fat accumulation on the lower body site compared to age matched Austrian males. This SAT-Top phenotype may play an important role for the increased cardiovascular risk seen in the Estonian population.</jats:p

Sports Participation outside School in Total Physical Activity of Children

This study of associations of sports participation with perceived and actual physical fitness, and total physical activity for 525 10- to 17-yr.-old boys and girls in groups of 10–11-yr. (56 boys and 64 girls), 12–13-yr. (68 boys and 68 girls), 14–15-yr. (70 boys and 71 girls), and 16–17-yr. (68 boys and 60 girls) was based on the Physical Activity Index derived from a questionnaire by Telama, Leskinen, and Young, and self-perceived endurance, strength, flexibility, and body composition. Questions about satisfaction with physical activity, participation in organized physical activity and competitions, or watching competitions were asked. Two EUROFIT tests were used, the 20-m endurance shuttle-run and sit-and-reach, plus the sum of 9 skinfold thicknesses. Children who participated in organized physical activity and in competitions had a higher Physical Activity Index. Passive watching of competitions was not related to children's physical activity or their perceived or measured motor abilities. </jats:p

Self-perceived and actual indicators of motor abilities in children and adolescents

Evaluation de la condition physique telle que perçue par les sujets eux-mêmes (capacité physique, endurance, force, souplesse, composition corporelle) au moyen du questionnaire de Delignières, Marcellini, Brisswalter et Legros (1994) et comparaison avec les résultats de tests Eurofit (course-navette sur 20 m, test de prise pour mesurer la force de serrage de la main, sit and reach test) chez 525 garçons et filles âgés de 10 à 17 ans