title: A test to approach maximal lactate steady-state in 12-year old boys and girls.
abstract: The purpose of this study was to measure the running velocity corresponding to the individual maximal lactate steady-state of a group of 12-year old boys and girls on a treadmill. This running velocity (v MLST) was compared with the maximal aerobic running velocity (v a max) at which maximal oxygen uptake (VO2 max) occurs. Thirteen pupils of the same school whose puberal maturation corresponded to the end of stage 2 and the beginning of stage 3 of Tanner: 6 boys (12.2 years old +/- 0.5, 38.4 +/- 2 kg, 150 +/- 4.8 cm: group 1) and 7 girls (12.3 years old +/- 0.5, 37.6 +/- 6 kg, 151.4 +/- 5.6 cm: group 2) carried out two tests at one week interval. The first test was a maximal incremental test for the determination of VO2 max with Douglas's bag method and v a max. The purpose of the second test was the determination of maximal lactate steadystate velocity (v MLST) With two stages of ten minutes at 60 +/- 5% and 74 +/- 4.5% v a max separated by 40 minutes of complete rest (Billat, 1992); VO2max and v a max were significantly different, equal to 49.4 +/- 7 ml.min-1.kg-1, 40.4 +/- 4.7 ml.min-1.kg-1 and 12.6 +/- 0.2 km.h-1, 11.2 +/- 1.2 km.h-1 for group 1 and 2 respectively (P < 0.05). Moreover, maximal lactate steady state velocity (v MLST) was respectively equal to 64.8 +/- 12.5% and 64.6% +/- 12.5% VO2 max respectively, representing 67.8 +/- 6.2% and 68.8% +/- 8.3% v a max and was not significantly different for group 1 and 2. In conclusion, this study shows that maximal lactate steady-state velocity is not significantly different between young boys and girls of 12 years old, when expressed in fraction of VO2 max or v a max. However, VO2 max and v a max were significantly higher in boys: +27.2 and +11.6% higher respectively.
authors.affiliation: Laboratoire STAPS, Université Paris XII, Créteil, France.
authors.forename: V
authors.initials: V
authors.lastname: Billat
authors.forename: A
authors.initials: A
authors.lastname: Gratas-Delamarche
authors.forename: M
authors.initials: M
authors.lastname: Monnier
authors.forename: P
authors.initials: P
authors.lastname: Delamarche
mesh_terms: D002648:Child; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007700:Kinetics; D007773:Lactates / Q000097:blood*; D019344:Lactic Acid; D008297:Male; D010101:Oxygen Consumption; D011627:Puberty; D012016:Reference Values; D012420:Running; D012727:Sex Characteristics
chemical_list: D007773:Lactates; D019344:Lactic Acid