INTRODUCTION: High-living and low-training (LHTL) altitude training may enhance endurance performance by its training and hypoxic influences. Our study ascertained possible effects of each of both. METHOD: Nine males (age: 22±2 yrs, BM: 74±3 kg, BH: 183±5 cm), members of XC-skiing national team were divided in two groups: live high - train low (LHTL) (n=6), and live low -train low (LLTL) (n=3). Both groups performed the same endurance training for 3 weeks in a range of 400 to 1500 m altitude. Training based on large volume with low and medium intensity. Subjects lived at 1500 m altitude. Additionally, the LHTL group slept in normobaric hypoxia (FiO2 = 0.18). All ski-runners performed a 3 min, submaximal test on a cycle-ergometer (3.5 W/kg) before and after the training period. They additionally repeated five times a maximal ski-roller 6.5 km uphill race with individual start. The first trial of this test was performed before, the next 3 were repeated throughout the altitude training period, and the last repetition was 3 weeks after the period of altitude training. Blood lactate [LA], pH, SaO2, relative muscle oxygen concentration (mO2) and pulmonary Ventilation (VE) were measured. Data were compared by using paired t-test and ANOVA for repeated measurements. RESULTS: The altitude training period of 3 weeks did not influence the velocity in the Skiroller maximal test differently when both groups were compared. The increase of [LA] during each repetition (delta LA) enhanced from 5.9±2.5 (pre), to 9.5±2.1 mmol/l post altitude training in LHTL (P<0.05). This was accompanied by unchanged values of pH decrease (-0.12±0.06 pre, and -0.15±0.05 post). There were no changes in LLTL group. During submaximal exercise on the cycle-ergometer delta LA remained unchanged in LHTL. However, pH decreased less (P<0.05) after altitude training (-0.06±0.01 pre, and -0.04±0.02 post), with accompanied enhancement of VE response (43±11 pre, and 49+7 l/min post; P<0.05). Values in LLTL did not change. mO2 was not influenced by altitude training except of its clear tendency to be higher in both groups. SaO2 did not change at all. DISCUSSION: Altitude training LHTL enhanced delta LA and also respiratory compensation of metabolic acidosis during maximal exercise. Because the enhancement in the blood pH occurred during submaximal exercise and without an enhanced delta LA in the same group, the increase of respiratory system sensitivity may be the mechanism, which was activated by hypoxic stimulus. This Stimulus was however too low to influence oxygenation in blood and muscle during submaximal exercise. CONCLUSION: LHTL altitude training enhances delta LA and respiratory compensation of metabolic acidosis in comparison to LLTL, probably by its hypoxic dose. Endurance training with large volume and low intensity seems to be responsible for an absent in enhancement of endurance performance during maximal exercise in both groups of previously endurance trained subiects.
© Copyright 2012 Science and Skiing V. 5th International Congress on Science and Skiing, Dec. 14 - 19, 2010, St. Christoph am Arlberg. Veröffentlicht von Meyer & Meyer Sport (UK) Ltd.. Alle Rechte vorbehalten. / Übersetzt mit https://www.DeepL.com/Translator