title: Oxygen uptake kinetics in trained adolescent females.
abstract: Little evidence exists with regard to the effect that exercise training has upon oxygen uptake kinetics in adolescent females.
  
  
  OBJECTIVE
  The aim of the study was to compare [Formula: see text] and muscle deoxygenation kinetics in a group of trained (Tr) and untrained (Utr) female adolescents.
  
  
  METHODS
  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.
  
  
  RESULTS
  Peak [Formula: see text] 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 [Formula: see text] 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).
  
  
  CONCLUSIONS
  Exercise training and/or genetic self-selection results in faster kinetics in trained adolescent females. The faster [Formula: see text] kinetics seen in the trained group may result from enhanced muscle oxygen utilisation.
authors.affiliation: Faculty of Health Sciences, Centre for Sport, Health and Exercise Research, Staffordshire University, Brindley Building, Leek Road, Stoke-on-Trent, ST4 2DF, UK, v.unnithan@staffs.ac.uk.
authors.forename: Viswanath B
authors.initials: VB
authors.lastname: Unnithan
authors.forename: Denise M
authors.initials: DM
authors.lastname: Roche
authors.forename: Max
authors.initials: M
authors.lastname: Garrard
authors.forename: Kathryn
authors.initials: K
authors.lastname: Holloway
authors.forename: Simon
authors.initials: S
authors.lastname: Marwood
mesh_terms: D000293:Adolescent; D056352:Athletes; D016022:Case-Control Studies; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D010101:Oxygen Consumption