Avaliação das respostas cardiovasculares, respiratórias e metabólicas ao treinamento muscular inspiratório utilizando a pressão inspiratória crítica em ciclistas recreacionais: estudo clínico randomizado, controlado e duplo cego

Abstract

Introduction: Inspiratory muscle training (IMT) has brought great benefits for improving physical performance in healthy and active individuals. However, there is no consensus regarding the better training load for this population. Objective: To evaluate the effect of critical inspiratory pressure (PThC) on physical performance and cardiovascular, respiratory and metabolic responses in recreational cyclists. Methods: Thirty-one men recreational cyclists (20-40 years old) were randomized to Sham Group (6cmH2O)(SG, n = 10), PThC Group (CPG, n = 10) and Group 60% of maximal inspiratory pressure (MIP) (60G, n = 10), taking into account age group and aerobic functional capacity. All participants were submitted to the following evaluations: pulmonary function test, respiratory muscle strength test (RMS), cardiopulmonary test (CPET), incremental inspiratory muscle endurance test (IMEi) [maximal sustained respiratory pressure for 1 minute (PThMAX)], using a linear load inspiratory resistor (PowerBreathe K5). During the evaluations, ECG (BioAmp FE132), peripheral pulse pressure, beat-to-beat (Finometer Pro) and thoracic movements were recorded using a chest strap (Marazza) and ventilatory and metabolic responses, using a system of expired gas measurements (ULTIMA MedGraphics/VMAX Encore 29). IMT lasted 11 weeks (3 times/week and 55 minutes/session). The data were analyzed by specific statistical tests (parametric or non-parametric) according to the data distribution and their respective variances. It will be established p <0.05. Results: The PThC was able to increase the peak power, evaluated in the CPET and inspiratory muscle strength and endurance. On the other hand, 60% of MIP increased peak power and peak oxygen consumption (VO2PEAK), assessed by CPET and IMS. All loads were able to increase MIP and PThMÁX, but none were able to change participants' breathing patterns or function pulmonary, after training. Conclusion: The IMT performed with PThC seems to be better for strength gain and inspiratory muscle endurance and the load of 60% of MIP better for increasing VO2PEAK. However, both loads (PThC and 60% of MIP) lead to improved performance of recreational cyclists.