Objective: Examination of the effect of endurance training in normoxia and hypoxia on maximal oxygen consumption (VO₂ max) and some ventilator parameters in cross-country skiers.

Materials and Methods: The study includes total 18subjects, 10 males and 8 females, who took part in the races at elite level, and practiced exercises for developing aerobic endurance on 6days a week. Totally 3 measurements were done during study, the first one of which was in Ankara (856 m), the second on the Mount Erciyes at the first day of acclimatization (2220 m, 4-6ºC) and the last one was again on Erciyes at the 7th day of acclimatization. All the tests were done at the same time of the day, 3hours after the lunch.

Results: The conclusion statistical analysis; in the comparison three tests of females, significant differences were found among the first and the second VO₂max scores at the level of p<0.05. There were significant differences between first and second vital capacity (VC), forced expiratory flow (FEV_25-75) scores of male (p<0.05)and results that 1st, 2nd VO₂max scores 2nd, 3rd VC, maximum voluntary ventilation (MVV), forced expiratory volume after 1s (FEV₁) at the first second, thus scores of male were significantly different at p<0.001 level. As a result of the comparison of both sex, it was found that in the first measurement FVC, FEV₁, FEV_25-75, MVV scores were statistically significant at the level of p<0.05, in the second measurement VC, forced vital capacity (FVC), FEV₁, FEV_25-75 at the level of p<0.001, in the third measurement VC, FVC, FEV₁, MVV at he level of p<0.05.

Conclusion: Consequently its determined that there is significant effect of endurance training on max VO₂ in normoxia and hypoxia and some ventilator parameters in cross-country skiers. ©2008, Firat University, Medical Faculty.