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The influence of training status on pulmonary VO2 recovery kinetics, and its interaction with maturity, has not been investigated in young girls. Sixteen prepubertal (Pre: trained (T, 11.4 ± 0.7 years), 8 untrained (UT, 11.5 ± 0.6 years)) and 8 pubertal (Pub: 8T, 14.2 ± 0.7 years; 8 UT, 14.5 ± 1.3 years) girls completed repeat transitions from heavy intensity exercise to a baseline of unloaded exercise, on both an upper and lower body ergometer. The VO2 recovery time constant was significantly shorter in the trained prepubertal and pubertal girls during both cycle (Pre: T, 26 ± 4 vs. UT, 32 ± 6; Pub: T, 28 ± 2 vs. UT, 35 ± 7 s; both p < .05) and upper body exercise (Pre: T, 26 ± 4 vs. UT, 35 ± 6; Pub: T, 30 ± 4 vs. UT, 42 ± 3 s; both p < .05). No interaction was evident between training status and maturity. These results demonstrate the sensitivity of VO2 recovery kinetics to training in young girls and challenge the notion of a "maturational threshold" in the influence of training status on the physiological responses to exercise and recovery. [ABSTRACT FROM AUTHOR]

This study examined longitudinal changes in the pulmonary oxygen uptake (pVO2) kinetic response to heavy-intensity exercise in 14-16 yr old boys. Fourteen healthy boys (age 14.1 ± 0.2 yr) completed exercise testing on two occasions with a 2-yr interval. Each participant completed a minimum of three 'step' exercise transitions, from unloaded pedalling to a constant work rate corresponding to 40% of the difference between the pVO2 at the gas exchange threshold and peak pVO2 (Δ). Over the 2-yr period a significant increase in the phase II time constant (25 ± 5 vs. 30 ± 5 s; p = .002, ω² = 0.34), the relative amplitude of the pVO2 slow component (9 ± 5 vs. 13 ± 4%; p = .036, ? 2 = 0.14) and the pVO2 gain at end-exercise (11.6 ± 0.6 vs. 12.4 ± 0.7 mL·min-1·W-1; p < .001, ω² = 0.42) were observed. These data indicate that the control of oxidative phosphorylation in response to heavy-intensity cycling exercise is age-dependent in teenage boys. [ABSTRACT FROM AUTHOR]

This study examined ergometer-specific relationships between short-term power and peak oxygen uptake (peak VO2) in children. Boys (n = 28) and girls (n = 28) age 11- 12 years completed two incremental tests to exhaustion on a cycle ergometer and motorized treadmill for the determination of peak VO2. In addition, they completed two 30 s "all-out" sprint tests, one on a cycle ergometer and one on a nonmotorized treadmill for the assessment of peak power (PP) and mean power (MP). Relationships between peak VO2 and short-term power measures were examined by sex for cycle- and treadmill-derived data using simple per-body-mass ratios and sample-specific allometric exponents to control for body size differences. From correlational analyses on scaled data, sex differences in responses were shown. In boys, PP and MP were unrelated to peak VO2 for cycle-derived measures but significantly related (r = 0.58 PP; r = 0.69 MP) for treadmill values. PP and MP were significantly related to peak VO2 for both modes of exercise in girls (r = .41-.68). In all but one case, correlation coefficients based on mass-related data were higher than those based on allometrically adjusted data. [ABSTRACT FROM AUTHOR]

These studies used multilevel modelling to examine optimised peak power (PP[sub opt]) from a force velocity test over the age range 12-14 years. In the first study, body mass, stature, triceps and subscapular skinfold thicknesses of boys and girls, aged 12.3 ± 0.3 y at the onset of the study, were measured on four occasions at 6 monthly intervals. The analysis was founded on 146 PP[sub opt] determinations (79 from boys and 67 from girls). Body mass and stature were significant explanatory variables with sum of two skinfolds exerting an additional effect. No gender differences were evident but PP[sub opt] increased with age. In the second study, thigh muscle volume (TMV) was estimated using magnetic resonance imaging at test occasions two and four. The analysis, founded on a subsample of 67 PP[sub opt] determinations (39 from boys and 28 from girls), demonstrated TMV to be a significant additional explanatory variable alongside body mass and stature with neither age nor gender making a significant contribution to PP[sub opt]. Together the studies demonstrate the influence of body size and TMV on young people's PP[sub opt]. [ABSTRACT FROM AUTHOR]

Examines the age and sex related differences in optimal peak power. Use of a force-velocity cycling test; Interpretation of cycle ergometer power tests; Effects of inertia on peak power.

Assesses the reliability of the ventilatory threshold using visual analysis and computerized v-slope method with children. Use of linear regression analysis; Repeatability of the v-slope method with children; Incorporation of computer programmes.

Evaluates the development of aerobic fitness during childhood and adolescence. Relationship between peak oxygen uptake and body size; Impact of maximal oxygen uptake on aerobic fitness; Assessment on the divergence of peak oxygen uptake.

Focuses on the statistical techniques for interpreting body size-related exercise performance during growth. Association of the processes of growth and maturation with dramatic changes in body size; Complexity of the application allometry to longitudinal data; Advantages of linear regression.

Examines the correlation between anaerobic performance and sexual maturation in children. Determination of peak and mean power; Development of aerobic fitness; Effect of body weight on physiological function.

This study was designed to investigate the influence of sexual maturity on peak VO2 and blood lactate responses to exercise using serum testosterone levels as an objective measure of maturity. Testosterone levels were determined in venous blood samples obtained from 12- to 16-year-old males (n =50). Peak VO2 and percentage of peak VO2 at blood lactate levels of 2.5 and 4.0 mmol·L-1 were determined during incremental treadmill running. Standard multiple regression revealed that body mass, age, and height explained 74% of the variance in peak VO2 scores. The addition of serum testosterone to the equation failed to produce a significant increase in the explained variance. Correlation coefficients between testosterone and the lactate variables were not significant (p > .05). These findings do not support the hypothesis that hormonal changes per se during sexual maturation play an important role in the development of peak VO2 and blood lactate responses to exercise. [ABSTRACT FROM AUTHOR]