Aeroobne töövõime 14–16aastastel neidudel

Töö eesmärgiks oli hinnata 14–16aastaste neidude maksimaalse hapnikutarbimise võimet (VO2max) ja töötada saadud andmete põhjal välja vastav hindeskaala praktiliseks kasutamiseks. Uuringus osales 102 tervet neidu erinevatest Tartu koolidest, kelle VO2max taseme näitajad määrati otsesel meetodil liikuval jooksurajal Conconi testi põhjal. Vaatlusaluste neidude VO2max absoluutne näitaja (±SD) oli 2,24 ± 0,45 l min-1 ja suhteline näitaja 39,35 ± 6,92 ml min-1 kg-1. Võrreldes selle töö tulemusi erinevate uuringutulemustega maailmast, võib järeldada, et eesti neidude aeroobse töövõime tase on suhteliselt sarnane eakaaslaste omaga mujal maailmas. Eesti Arst 2004; 83 (6): 371–37

Die Verminderung von relativer maximaler Sauerstoffaufnahme bei geschlechtsreifen Mädchen

The purpose of this study was to verify the previous results indicating reduced peak VO2 normalized to body mass in girls of advanced sexual maturation. 31 girls aged 11 to 15 years were divided by Tanner’s sexual maturation stages into groups of prepubertal (stage I), pubertal (stages II, III, IV) and postpubertal (stage V) girls. The peak VO2 and the ventilatory threshold were assessed with the aid of a cycloergometric incremental exercise test. Peak VO2 (l/min) was higher in pubertal than prepubertal girls (1.89±0.44 vs. 1.72±0.32, p<0.05). The difference between pubertal and postpubertal girls was insignificant. Relative maximum VO2 did not differ between prepubertal and pubertal girls. In postpubertal adolescents this value was 13% lower than in pubertal girls (p<0.05). An increase of the body mass index showed that in sexual maturation stage V the gain of body mass was relatively more pronounced than the increase in body height. The ventilatory threshold did not differ between the maturation groups.Uvod Neka su istraživanja pokazala da vrijednost relativnog VO2max ne ovisi o spolnom sazrijevanju dječaka. Mebutim, opažanja te pojave u djevojčica pokazala su da je vrijednost VO2max niža u kasnijim fazama spolnog sazrijevanja nego li u spolno manje zrelih djevojcica (Laaneots i sur., 1996). Cilj ovog istraživanja bio je provjeriti smanjuje li se relativni maksimalni primitak kisika s napredovanjem spolnog sazrijevanja u djevojčica. Metoda Uzorak ispitanica činila je 31 djevojčica u dobi od 11 do 15 godina. Uzorak je prema Tannerovoj ljestvici podijeljen na podgrupu predpubertetskih (faza I), pubertetskih (faza II,III, IV) i postpubertetskih djevojcica (faza V). Maksimalni VO2 i ventilacijski prag procjenjivani su progresivnim testom na biciklergometru. Rezultati Vrijednost maksimalnog VO2 (l/min) bila je viša u pubertetskih nego predpubertetskih djevojčica (1.89 ± 0.44 nasuprot 1.72 ± 0.32). Raz- lika izmebu pubertetskih i postpubertetskih djevojčica (1.88 ± 0.46) nije bila statistički značajna. Nije se pokazala statistički značajna razlika u vrijednosti relativnog maksimalnog primitka kisika između predpubertetskih (43 ± 7.3) i pubertetskih (39 ± 9.8) djevojčica. Međutim, ta vrijednost u postpubertetskih djevojcica (34 ± 0.46) bila je oko 13% niža nego u djevojčica u pubertetu (p<0.05). Povecanje indeksa tjelesne mase (sa 18.8 na 20.4 u prosjeku) pokazalo je da je u petoj (V) fazi spolnog sazrijevanja povećanje tjelesne mase relativno više istaknuto nego tjelesni rast u visinu. Tako je vidljivo da korelacija između veličine tijela i maksimalnog VO2 nakon ulaska u petu fazu spolnog sazrijevanja prestaje. Ne postoji statistički značajna razlika između grupa ispitanica s obzirom na vrijednost ventilacijskog praga. Dok je anaerobni prag prije svega određen oksidativnim kapacitetom mišića, smanjenje relativnog maksimalnog VO2 u djevojčica u kasnijoj fazi spolnog sazrijevanja nije bilo povezano s promjenama oksidativnog mišićnoga kapaciteta. Zaključak U djevojčica se spolno sazrijevanje povezuje sa smanjenjem relativnog maksimalnog primitka kisika, što se javlja paralelno s povećanjem tjelesne mase u odnosu na povećanje visine. Prema konstantnim vrijednostima anaerobnog praga, smanjenje relativnog VO2max u djevojčica u naprednoj fazi spolnog razvoja očigledno nije bilo povezano sa smanjenjem oksidativnog mišićnoga kapaciteta.Das Ziel dieser Studie war, die früheren Forschungsergebnisse, die die Verminderung von relativer maximaler Sauerstoffaufnahme bei geschlechtsreifen Mädchen zeigten, zu überprüfen. 31 Mädchen (im Alter 11-15 Jahre) wurden laut Tanners Stufen der Geschlechtsreife in drei Gruppen, nämlich, Vorpubertät (Stufe I), Pubertät (Stufen II, III, IV) und Nachpubertät (Stufe V), geteilt. Die maximale Sauerstoffaufnahme und die ventilatorische Schwelle wurden mit Hilfe des Fahrradergometer-Stufenübung-Testes bestimmt. Maximale Sauerstoffaufnahme (l/min) war bei den Mädchen, die in der Pubertätsgruppe waren, höher als bei Mädchen, die sich in der Vorpubertätsgruppe befanden (1,89±0,44 und 1,72±0,32). Der Unterschied zwischen den Mädchen, die in der Pubertätsphase waren, und Mädchen in der Nachpubertätsphase, war nicht bedeutend. Relative maximale Sauerstoffaufnahme ist kein Hriterium, das die Mädchen, die in der Vorpubertätsphase sind, und Mädchen in der Pubertätsphase, voneinander unterscheidet. Bei Mädchen, die sich in der Nachpubertätsphase befinden, war dieser Wert 13% niedriger als bei Mädchen in der Pubertätsphase (p<0,05). Der erhöhte Hörpermassenindex zeigte, dass in der fünften Stufe der Geschlechtsreife die Hörpermassenzunahme größer war als Hörperhöhenzunahme. Die ventilatorische Schwelle war kein Hriterium, das die verschiedenen Geschletsreifengruppen voneinander unterscheidet

Comparison of the hormonal responses to exhaustive incremental exercise in adolescent and young adult males

OBJECTIVE: Evaluate hormonal responses to incremental-stage exercise (EX) test to exhaustion in adolescents. SUBJECTS AND METHODS: Adolescents were tested at 16 years of age in Tanner Stage 4 (TS4) and at 17 years of age in Tanner Stage 5 (TS5) (n = 6). Adults were tested at 21 ± 1 y. (X ± SD) (n = 4) and served as controls. Blood samples were taken at rest, at the end of each EX stage. RESULTS: Main effects for EX in cortisol (p < 0.01, increasing with each EX stage) and for subject group for testosterone (T) occurred (p < 0.01; TS4 < TS5, adults). Interaction effect of group by EX stage occurred for GH (p < 0.05). GH increased in response to EX in all groups, however, the magnitude of increase was significantly less for TS5 and adults than TS4. CONCLUSIONS: Differences in T and GH responses for TS4 than those for TS5 and adults reflect the differing maturation levels of the endocrine system between Tanner Stages. TS5 adolescents are more similar to young adults in hormonal responses to EX than are TS4 adolescents

Effects of acute ingestion of sodium citrate on metabolism and 5-km running performance : a field study

Effets de l'apport d'une solution tampon contenant du citrate de sodium sur la rétention d'eau, le volume plasmatique, le pH sanguin et la performance au cours d'une épreuve de course sur 5 km chez des sujets masculins entraînés

THE EFFECTS OF SODIUM CITRATE INGESTION ON METABOLISM AND 1500-M RACING TIME IN TRAINED FEMALE RUNNERS

The purpose of the study was to assess the effects of sodium citrate ingestion on the metabolic response to exercise and performance in a 1500-m competitive run in trained female middle-distance runners in field conditions. Seventeen athletes (mean (± SD) aged 18.6 ± 2.5 years, VO2max 55.2 ± 7.6 ml·kg-1·min-1) competed in two 1500-m races following ingestion of 0.4 g·kg-1 body mass of sodium citrate (CIT) and placebo (PLC - 1.0% solution of NaCl). The two substances, CIT and PLC were administered in 800 ml of solution in a randomly assigned double-blind crossover manner. Capillary blood samples were analysed for lactate, glucose, haemoglobin and haematocrit before administering the solutions (baseline) as well as before and after both 1500-m races. The athletes' times for trials CIT and PLC were 321.4 ± 26.4 and 317.4 ± 22.5 s, respectively (p > 0.05). A greater relative increase in plasma volume after administering the experimental solution, an increased body mass (by 0.4 kg; p = 0.006) immediately before the race and a restrained increase in blood glucose concentration (by 2.5 ± 1.2 mmol·l-1 vs 3.4 ± 0.8 mmol·l-1; p = 0.002) during the race were observed in the CIT trial compared to the PLC. A significant relationship was observed between body mass of the subjects immediately before the race and performance time (r = 0.374; p = 0.029). There were no between-treatment differences in heart rate in any stage of the run or in blood lactate accumulation during the race (final concentration of lactate was 14.4 ± 3.0 mmol·l-1 and 13.4 ± 2.5 mmol·l-1 (p > 0.05) in the CIT and PLC trials, respectively). The results suggest that sodium citrate induces an increase in water retention before exercise and may modify carbohydrate metabolism in high intensity running, but does not improve performance in 1500-m competitive run in female middle-distance runner