Fadiga ventilatória de corredores treinados após exercício de corrida intervalado de alta intensidade

Abstract

Introduction: High-intensity aerobic exercises, both continuous (HICT) and intervals (HIIT) are important components of long-distance runners training routine. During HICT, runs are sustained, without interruption, at intensities near the respiratory compensation point (RCP). On the other hand, HIIT is characterized by the alternation of effort phases with intensities above the CRP, followed by a passive or active recovery phase at low intensities (close to the anaerobic threshold). HIIT has been shown to be efficient in inducing increase in inspiratory muscle strength since, during the exertion phases, great respiratory work is performed, with the mobilization of large volume tidal (VT) and high respiratory rate (RR), which can cause ventilatory muscle fatigue immediately after the training session. Objectives: To test the hypothesis that one HIIT training session causes greater ventilatory muscle fatigue, inferred by the reduction of inspiratory force and respiratory endurance, than one HICT training session in long distance runners familiar with both types of training. Methodology: Ten trained runners (25.4 ± 4.7 years of age and VO2max of 63.0 ± 6.6 ml / kg / min) participated in the study. There were 3 visits to the laboratory. In the first, the maximal ergospirometric test was performed to measure maximal oxygen uptake (VO2max) and velocity associated with VO2max (vVO2max), and familiarization with the ventilatory tests. In the second and third visits, the volunteers did, in a randomized sequence, two types of training of the same duration and mean intensity: HICT (14 minutes at 85% of vVO2max) and HIIT (7 efforts of 1 minute at 110% of vVO2max interspersed by intervals of 1 minute to 60% of vVO2max). Before (at the end of warm-up) and after both training protocols, measurements of inspiratory strength, by maximal inspiratory pressure (MIP), respiratory endurance, by fixed load test (TEDCF), and perceived exertion (RPE) were performed. During the exercise, VO2, RR and TC were collected. The results were presented in mean and standard deviation. The differences between the means were tested by analysis of variance for repeated measure followed by the Tukey post-hoc test (p <0.05) or Student “t” test for dependent samples. Results: Both training protocols (of the same duration and mean intensity) cause the same oxygen consumption, but the RR, TC and RPE were higher in HIIT. After the training sessions, there was no reduction of the inspiratory force (MIP) and there was a similar reduction in the respiratory endurance (TEDCF). Conclusion: When paired by duration and mean intensity, one HIIT or HICT training session present the same VO2, although HIIT has higher RR, TC and RPE. After the training sessions, there is no reduction of the inspiratory strength (MIP) and a similar reduction of the respiratory endurance (MIP).