The slow component of O2 uptake kinetics during high-intensity exercise in trained and untrained prepubertal children

Int J Sports Med. 2000 Jan;21(1):31-6. doi: 10.1055/s-2000-8856.


The aim of the present study was to investigate the O2 uptake slow component in prepubertal children of different aerobic capacity during high intensity exercise. Twenty-three (12 well-trained, T and 11 untrained, U subjects) 10-13 year old prepubertal children took part in 3 tests: one incremental test to determine the maximal aerobic power (PMA) and anaerobic threshold (LAT); two constant-power tests performed at intensities corresponding to 80%LAT and 90%PMA. Oxygen uptake (VO2), heart rate, ventilation (VE) and lactate ([L]s) were evaluated during each test. A monoexponential + linear term model (starting after phase 1) was used to assess VO2 kinetics during both constant-power tests. Our results showed that a slow component, represented by the linear coefficient (S) of the mathematical model, was present during the 90%PMA test only (S = 0.86 +/- 0.48 ml x min(-2) x kg(-1) for the whole population). No relationships were found between either S and VE or [L]s, showing that, at least in prepubertal children, these factors play a minor role in the explanation for the VO2 slow component. The slow component contributed approximately to the same amount of the total VO2 response in both groups (T: 21.4 +/- 8.0, U: 19.3 +/- 3.9%, ns). In conclusion, as previously described in adults, our data demonstrated the existence of a slow component in prepubertal children during high-intensity exercise. Moreover, this slow component was similar in trained and untrained children, exercising at the same relative intensity.

MeSH terms

  • Adolescent
  • Child
  • Exercise / physiology*
  • Female
  • Humans
  • Male
  • Models, Theoretical
  • Oxygen Consumption*
  • Physical Endurance / physiology*
  • Puberty
  • Pulmonary Gas Exchange
  • Time Factors