TRAINING PRODUCES FASTER VO2 ON-KINETICS IN GIRLS
Unnithan, V. B., Roche, D. M., Garrard, M., Holloway, K., & Marwood, S. (June 03, 2010). Oxygen uptake kinetics in trained female adolescents. Presentation 2010 at the 2010 Annual Meeting of the American College of Sports Medicine, Baltimore, Maryland; June 2-5.
This study compared VO2 and muscle deoxygenation kinetics in a group of trained (N = 12) and untrained (N = 8) female adolescents. Ss underwent two, 6-minute exercise transitions at a workload equivalent to 80% of lactate threshold from a 3-minute baseline of 10W. Ss had a passive rest period of 45-minutes between each square-wave transition. Breath-by-breath oxygen uptake and muscle deoxygenation (deoxyhaemoglobin signal from near infrared spectroscopy) were measured throughout the square wave transitions and were modeled via a monoexponential decay with a delay relative to the start of exercise.
Peak VO2 was significantly greater in the trained group when compared to the untrained group. The time constant of the VO2 on-kinetics was significantly faster in the trained girls compared to the untrained girls. There was no between-group difference in the time constant for muscle deoxygenation kinetics.
Implication. Exercise training results in faster VO2 on-kinetics in adolescent females. The lack of difference in muscle deoxygenation kinetics suggests that cardiovascular and peripheral adaptations were similarly responsible for the faster on-kinetics.
[The on-kinetics of oxygen consumption (VO2) describes the initial rate change in oxygen uptake as exercise is performed.]
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