ABSTRACT
The aim of this study was to investigate the effects of 3 weeks high-intensity interval training (HIIT) on ventilatory efficiency (VE/VCO2 slope) in endurance athletes. Sixteen male well-trained (67.72â¯mlâ¯kgâ¯min-1) athletes participated in this study. Each participant performed an incremental exercise test with gas analysis (i.e. VE, VO2) and a 400â¯m running field test (T400m) before and after the 3 weeks intervention period. HIIT group (HIITG) performed 11 HIIT sessions consisting of four 4-min interval bouts at an exercise intensity of 90-95% of the VO2max, separated by 4-min active recovery periods (work/rest ratioâ¯=â¯1:1). No significant differences were found in the parameters studied. Ventilatory efficiency (up to VT2 and up to exhaustion) did not show any change in HIITG after training intervention (ESâ¯=â¯0.24 HIITG; ESâ¯=â¯0.21 CG). No significant changes were observed on ventilation (VEmax; ESâ¯=â¯0.38). VO2max and T400â¯m did not show a significant improvement after the training period (no interaction timeâ¯×â¯group, pâ¯<â¯.05) (ESâ¯=â¯0.43 and ESâ¯=â¯0.75 respectively). These results do not support the hypothesis that 3 weeks of HIIT could modify the ventilatory efficiency response in well-trained athletes. Furthermore, they show the lack of relationship between ventilatory efficiency and sport performance.
Subject(s)
Athletes , High-Intensity Interval Training/methods , Pulmonary Ventilation/physiology , Respiration , Adult , Analysis of Variance , Blood Gas Analysis , Exercise Test , Follow-Up Studies , Humans , Male , Physical Endurance , Random Allocation , Time Factors , Young AdultABSTRACT
PURPOSE: This study examined the haematological adaptations to high-intensity interval training (HIT), i.e. total haemoglobin mass (tHb-mass), blood volume (BV), and plasma volume (PV), and its effects on VO2max in well-trained athletes. METHODS: Twenty-seven male and eight female well-trained (VO2max 63.7 ± 7.7 ml/min/kg) athletes were randomly assigned to the HIT (HITG, N = 19) or the control group (CG, N = 16). Over a 3-week period, the HITG performed 11 HIT sessions, consisting of four 4-min interval bouts at an exercise intensity of 90-95 % of the individual maximal heart rate (HRmax), separated by 4-min active recovery periods. Before and 5 ± 2 days after the intervention, tHb-mass, BV and PV were determined by the CO-rebreathing method. VO2max was assessed in a laboratory treadmill test. RESULTS: tHb-mass (from 753 ± 124 to 760 ± 121 g), BV (from 5.6 ± 0.8 to 5.6 ± 0.9 l) and PV (from 3.2 ± 0.5 to 3.2 ± 0.5 l) remained unchanged after HIT and did not show an interaction (group × time). Within the HITG, VO2max improved from baseline by +3.5 % (p = 0.011), but remained unchanged in the CG. No interaction (group × time) was seen for VO2max. The HITG showed a significant reduction in HRmax compared to the baseline measurement (-2.3 %, p ≤ 0.001), but HRmax remained unchanged in the CG. There was a significant interaction (group × time) for HRmax (p = 0.006). Also, oxygen pulse significantly increased only in HITG from 22.9 ± 4.4 to 23.9 ± 4.2 ml/beat, with no interaction (p = 0.150). CONCLUSIONS: Eleven HIT sessions added to usual training did neither improve VO2max nor haematological parameters compared to the CG.