title: The slow component of O2 uptake kinetics during high-intensity exercise in trained and untrained prepubertal children.
abstract: 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.
authors.affiliation: Laboratory of Exercise Physiology, Faculty of Sport Sciences, University of Orléans, France. Philippe.Obert@univ-avignon.fr
authors.forename: P
authors.initials: P
authors.lastname: Obert
authors.forename: C
authors.initials: C
authors.lastname: Cleuziou
authors.forename: R
authors.initials: R
authors.lastname: Candau
authors.forename: D
authors.initials: D
authors.lastname: Courteix
authors.forename: A M
authors.initials: AM
authors.lastname: Lecoq
authors.forename: P
authors.initials: P
authors.lastname: Guenon
mesh_terms: D000293:Adolescent; D002648:Child; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D010101:Oxygen Consumption; D010807:Physical Endurance / Q000502:physiology*; D011627:Puberty; D011659:Pulmonary Gas Exchange; D013997:Time Factors