N Armstrong

..With body size and fatness controlled for, boys have greater SVs than girls when exercising at the same absolute VO2, Q and treadmill running speed. Age and maturation do not exert independent effects on either Q or SV...

..Reductions in muscle activity were greatest for the drop jump, suggesting an influence of muscle stretch and loading on reduced muscle activity when fatigued...

..To examine the ventilatory responses of prepubescent children to submaximal and peak exercise using appropriate allometric modeling to control for differences in body size...

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..The chapter therefore concludes with a discussion of insights into aerobic fitness provided by the emerging database on young people's oxygen uptake kinetics responses to exercise of different intensities...

..It therefore appears that we might have available the tools necessary to answer some of the elegant questions raised by Professor Bar-Or over 25 years ago...

..To analyse aerobic fitness and its relationship with sport participation, exercise training and habitual physical activity (HPA) during youth...

..Boys are not mini-men and coaches and parents should focus on providing opportunities for all boys and on nurturing talent irrespective of the ticking of individual biological clocks...

..Empirical evidence strongly indicates that both trained and untrained young people can benefit from endurance training but the relative intensity of exercise required for optimum benefits is higher than that recommended for adults...

..CONCLUSION: Few children experience extended bouts of PA, and from 11-13 y, PA decreases, with more girls than boys becoming inactive. The data emphasize the importance of promoting active lifestyles during youth...

..Fat-free mass was the dominant influence on the growth of VO2peak but the multilevel regression models demonstrated that, with body size and fatness allowed for, VO2peak increased with age and maturation in both sexes...

..This effect may have been masked in previous studies by the inappropriate use of peak VO2 in ratio with body mass...

..The body mass exponent almost doubled, but the age-by-gender interaction term was consistent with the initial model...

..To examine short term power output during growth and maturation using a multilevel modelling approach...

..The influences of age, body size, skin-fold thickness, gender, and maturation on the short-term power output of young people were examined using multilevel modelling...

..When differences in body mass and skinfolds were controlled for, there was still a difference between the sexes in submaximal VO2, with girls becoming increasingly more economical with age...

..Age, maturity and thigh muscle CSA were all non-explanatory variables in the production of PET and PFT once body size had been controlled for...

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..05). In conclusion, thigh muscle volume exerts a positive influence on young people's short-term power output, which is additional to the effects of body mass, sum of skinfolds and age...

..Exercise testing is a valuable prognostic tool and exercise training has many health benefits in cystic fibrosis (CF). The objective of this study was to survey the provision of exercise testing and training in UK CF clinics...

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..Despite the decrease in power and force outputs with R180, the young men were able to maintain their running velocity during the test...

..A significant relationship was found between VO2(peak) and early VO2 recovery (r = -0.39, P = 0.044) in the children with CCD, showing that a greater aerobic fitness corresponded with a faster recovery...

..To investigate whether aerobic fitness is associated with skin microvascular function in healthy adults with an increased risk of developing Type 2 diabetes...

..Sex differences in peripheral factors such as muscle fibre type profile, may affect A-VO(2) difference and underlie prepubertal boys' higher peak V O(2)...

..The unique issues and considerations of providing continued physiological support to young athletes are discussed...

..This study tested the hypothesis that the muscle metabolic responses of 9- to 12-yr-old children and young adults during incremental quadriceps exercise are dependent on age and sex...

..In addition, an overview of the basic principles of (31)P-MRS and its application to the study of muscle metabolism is provided and discussed in relation to child-specific methodological concerns when using this technique...

..To determine the relationship between aerobic fitness (peak VO2) and the volume of visceral adipose tissue (VAT) in children...

..05). A significant relationship between the time constant and peak VO2 was found only in adult males (P<0.05). A shorter time constant in children may reflect an enhanced potential for oxidative metabolism...

..To determine the ability of air displacement plethysmography (ADP) to predict visceral adipose tissue (VAT) volume in children...

..VO2 and tau in children. However, sex differences in the response to exercise intensities above the anaerobic threshold are identified and discussed...

..048). These results suggest that phase II Vo(2) kinetics in young boys is principally limited by intrinsic muscle metabolic factors, whereas the Vo(2) total phase II and slow component amplitudes may be O(2) delivery sensitive...

..Future studies should preferably be longitudinal in nature and examine known covariates simultaneously using appropriate statistical techniques...

..The data demonstrate that children do display a slow-component response to exercise and are consistent with an age-dependent change in the muscles' potential for O(2) utilization...

..To investigate the reliability of heart rate variability (HRV) measures at rest and during light exercise in children...

..01). The results of this study show that the control of oxidative metabolism at the onset of high intensity exercise is adult-like in 13-year-old children, but that matching of oxygen delivery to extraction is more precise in adults...

..Overall, the data support the view that at the onset of exercise children have an enhanced potential for oxidative metabolism in the myocyte compared with adults...

..It was concluded that the nature of the response to heavy intensity exercise in children is similar to that previously reported with adults and that the response should be modelled accordingly...

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..05. Hence, for researchers solely interested in PVO2 values, a shorter but more intensive protocol provides an alternative method to the traditional ramp aerobic test...

..Furthermore, children and adults experienced greater fatigue during running compared to cycling. This last result may be attributed to additional muscle recruitment during sprint running...

..9 (3.7)%]. Sex differences in the kinetic response to heavy-intensity exercise were identified and suggest that during the prepubertal years, sex differences exist in the ability to deliver and/or utilise oxygen in children...

..The imposition of energy expenditure through exercise of either low or high intensity resulted in no detectable increase in energy intake in the short term...

..However, the objectively determined IT(Pi/PCr) and END(Pi/PCr) displayed poor reliability...

..It is concluded that the present performance test is reliable in adolescent cyclists with lower variation between trials 2 and 3...

..CONCLUSION: Use of only linear dimensions rather than muscle CSA to account for differences in size may have clouded our understanding of strength development in children...