01-01-2015 | Original Article
Oxygen uptake kinetics in trained adolescent females
Published in: European Journal of Applied Physiology | Issue 1/2015
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Little evidence exists with regard to the effect that exercise training has upon oxygen uptake kinetics in adolescent females.
Purpose
The aim of the study was to compare \(\dot{V}{\text{O}}_{2}\) and muscle deoxygenation kinetics in a group of trained (Tr) and untrained (Utr) female adolescents.
Method
Twelve trained (6.4 ± 0.9 years training, 10.3 ± 1.4 months per year training, 5.2 ± 2.0 h per week) adolescent female soccer players (age 14.6 ± 0.7 years) were compared to a group (n = 8) of recreationally active adolescent girls (age 15.1 ± 0.6 years) of similar maturity status. Subjects underwent two, 6-min exercise transitions at a workload equivalent to 80 % of lactate threshold from a 3-min baseline of 10 W. All subjects had a passive rest period of 1 h between each square-wave transition. Breath-by-breath oxygen uptake and muscle deoxygenation were measured throughout and were modelled via a mono-exponential decay with a delay relative to the start of exercise.
Result
Peak \(\dot{V}{\text{O}}_{2}\) was significantly (p < 0.05) greater in the Tr compared to the Utr (Tr: 43.2 ± 3.2 mL kg−1 min−1 vs. Utr: 34.6 ± 4.0 mL kg−1 min−1). The \(\dot{V}{\text{O}}_{2}\) time constant was significantly (p < 0.05) faster in the Tr compared to the Utr (Tr: 26.3 ± 6.9 s vs. Utr: 35.1 ± 11.5 s). There was no inter-group difference in the time constant for muscle deoxygenation kinetics (Tr: 8.5 ± 3.0 s vs. Utr: 12.4 ± 8.3 s); a large effect size, however, was demonstrated (−0.804).
Conclusion
Exercise training and/or genetic self-selection results in faster kinetics in trained adolescent females. The faster \(\dot{V}{\text{O}}_{2}\) kinetics seen in the trained group may result from enhanced muscle oxygen utilisation.