The purpose of this study was to examine the influence of biological maturation on the pattern of fat and carbohydrate metabolism during exercise in early-pubertal (EP), mid-pubertal (MP), and late-pubertal (LP) males. Nine boys, Tanner stage I (EP) (10.3 ±0.9 years), 12 boys, Tanner stage 2/3 (MP) (12.3 ± 1.9 years), and 11 boys, Tanner stage 4/5 (LP) (15.0 ± 0.8 years) were subjects. Maximal aerobic capacity (VO2max) was assessed and, on a separate day, 5, 5-minute exercise bouts on a cycle ergometer at 30, 40, 50, 60, and 70% Of VO2max were performed in a fasted state. Fuel use was calculated at each intensity using steady-state V02 and the respiratory exchange ratio (RER). A one-way ANOVA was used to analyze physical characteristics and maximal exercise responses between groups. A two-way (group x intensity) ANOVA was used to analyze responses during submaximal exercise. Statistical significance was set at p < 0.05. VO2max (ml•kg-l.min 1) was not different between groups. At each intensity, % VO2ma., was similar between groups (p > 0.05). Significant interactions were found for RER, carbohydrate utilization, % fat utilization, and lactate concentration. Post hoc analyses revealed that at all intensities, % fat use and fat oxidation rates were higher and carbohydrate use and carbohydrate oxidation rates were lower in MP versus LP. In comparison, between EP and LP, % fat use was higher and % carbohydrate use was lower at 50-60% of VO2max, while fat oxidation rate was higher in EP versus LP at 40, 50, and 60% of VO2max. The only differences between EP and MP were for % fat and carbohydrate use at 30% of VO2max. Lactate concentrations were also lower in EP and MP than in LP at intensities corresponding to 50, 60, and 70% of VO2m., while no differences were observed between EP and MP at any intensity. The lack of a significant difference in substrate utilization or lactate concentrations between EP and MP at the majority of exercise intensities, suggest that the development of an adult-like metabolic profile occurs in the transition from mid-puberty to late-puberty. / School of Physical Education
| Identifer | oai:union.ndltd.org:BSU/oai:cardinalscholar.bsu.edu:handle/187664 |
| Date | January 2003 |
| Creators | Stephens, Brooke R. |
| Contributors | Mahon, Anthony D. |
| Source Sets | Ball State University |
| Detected Language | English |
| Format | vi, 79 leaves : ill. ; 28 cm. |
| Source | Virtual Press |
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