Abstract:
The purpose of the present study was to determine the effects of normoxic and normobaric hypoxic high-intensity interval training (HIIT) on aerobic fitness and tolerance to fatigue in youth soccer players. All subjects were male youth soccer players (n = 32), aged 15-16 years. Players were separated into two groups including HIIT group in normoxia (FiO2 = 20.9 % / NG; n = 16) and HIIT group in normobaric hypoxia (FiO2 = 15.3 % / HG; n = 16). Players performed 4 min at 9095 % of maximal heart rate (HRmax) for alternated with 3 min at 6070 % of HRmax 4-5 sets per day, 3 days per week for 8 weeks. The measurements of general physiological characteristics, aerobic fitness and tolerance to fatigue were assessed before, after 4 weeks and after 8 weeks of training. A 2 x 3 (group x time) ANOVA with repeated measures followed by Bonferronis multiple comparisons was used to analyze the data. A significance level of 0.05 was considered for statistical significance. The results showed that after 4 weeks and 8 weeks, the mean values of weight, height, BMI, body fat, heart rate, systolic blood pressure and diastolic blood pressure were not significantly difference between HG and NG. The mean values of HRmax, maximal O2 consumption , anaerobic threshold after 4 weeks and 8 weeks and distance covered in the Yo-Yo test after 8 weeks training in HG was higher than in NG (p<0.05). The mean values of blood lactate at 75 min, blood lactate at the fatigue point, penalty time and global performance time of soccer passing test after 8 weeks training in HG were lower than in NG (p<0.05). In conclusions, HIIT in normobaric hypoxia had greater effects on aerobic fitness and tolerance to fatigue than HIIT in normoxia. This indicated that HIIT in normobaric hypoxia can be used as a training model for youth soccer players.