Effect of Inspiratory Muscle Training on Recreational Cyclists

Phase 2

• Conditions: Healthy

• Registration Number: NCT02984189
• Lead Sponsor: Universidade Federal de Sao Carlos

Brief Summary

Introduction: The inspiratory muscle training (IMT) has showed great benefits to the respiratory, autonomic system, and mainly to the improvement of physical performance in healthy subjects. The latter is related to the improvement of respiratory muscle strength, decreased of dyspnoea, peripheral fatigue and delay in activation of muscle metaboreflex during exercise. However, there is no consensus about the best training load to IMT, because the prescription has been done only using percentage of the maximal inspiratory pressure (MIP), and 60% of MIP has been the most used. Therefore, the IMT prescription protocol that takes into account the respiratory muscle strength and endurance can provide additional benefits to protocols commonly applied, once that respiratory muscle differs from the other muscles due to its greater muscle endurance. In the sense, the IMT using inspiratory critical pressure (PThC) comes up with an alternative, since the PThC calculation considers these characteristics. Objective:To evaluate the effect of the IMT, using PThC, on cardiovascular, respiratory, metabolic and autonomic responses in recreational cyclists and compare it to a IMT using 60% of MIP. Methods: Thirty men recreational cyclists (20-40 years), will be randomized to placebo group (PG, n = 10), PThC group (PTHCG, n = 10) and 60% of MIP group (60G, n = 10), taking into account the age and functional aerobic capacity. All subjects will perform the following evaluations: cardiovascular autonomic tests \[heart rate variability (HRV) and blood pressure variability (BPV) at rest and after active postural change\], pulmonary function testing, respiratory muscle strength (RMS) test, cardiopulmonary exercise testing (CPET), incremental respiratory muscle endurance test (iRME) \[maximum respiratory pressure sustained for 1 minute (PThMAX)\] and constant respiratory loads test (95%, 100% and 105% of PThMAX), both using an linear inspiratory load resistor (PowerBreathe K5). The PThC will be obtained from the linear regression using the time(TLIM) of and load of each constant test (95%, 100% and 105% PThMAX). During evaluations, the ECG (BioAmp FE132), blood pressure (BP), using Finometer Pro (Finapress Medical Systems) and respiration (Marazza) signals will be acquired. The signals will be coupled by data acquisition and analysis device (Power Lab 8/35) and sampled at 1000 Hz. Moreover, the oxyhemoglobin, deoxyhemoglobin and total hemoglobin responses will be measured by near-infrared spectroscopy (NIRS) (Oxymon MKIII), sampled at 250Hz. The IMT will be performed for 11 weeks (3 times/week, 1-hour duration). The session will consist of 5-min warm-up (50% of the training load) and 3 sets of 15 minutes (breathing against 100% of the training load) with 1-min interval between them. Heart rate and BP will be monitored in all training sessions. The RMS, iRME, respiratory constant load tests and CPET will be performed before and after the training, and in the 3rd and 7th week (for training load adjustment). The pulmonary function testing and the cardiovascular autonomic tests will be performed only before and after training. The data will be analyzed by specific statistical tests (parametric and nonparametric) according to the data distribution and their respective variances. Significance will be set at p\<0.05. Expected results: It is expected that the training performed by PTHCG, when compared to training performed by 60G and PG, promotes: greater improvementin workload (Watts) and peak oxygen uptake (VO2peak); increasing in MIP and iRME; decreasing of dyspnoea and peripheral fatigue; delay in activation of muscle metaboreflex in the CPET and iRME; improvement incardiac parasympathetic autonomic modulation and reducing cardiac and peripheral sympathetic modulation. Moreover, it is expected that the results can provide information for a better understanding of the responses obtained by the PThC training in the different evaluated systems. In addition, these results will allow the use of this method by health professionals as a new assessment tool and IMT prescription.

Detailed Description

Not available

Study Timeline

• Study Start: 2016-02
• Study First Submitted: 2016-11-29
• Status Verified: 2016-12
• Study First Submitted QC: 2016-12-01
• Last Update Submitted: 2016-12-01
• Study First Posted: 2016-12-06
• Last Update Posted: 2016-12-06
• Primary Completion: 2018-12
• Study Completion: 2019-02

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: Male
• Target Recruitment: 30

Inclusion Criteria

• Apparently Healthy;
• Practicing cycling for at least 6 months continuous and at least 150 min weekly as active [by the American College of Sports Medicine (2011)].

Exclusion Criteria

• Participants can not be: smokers, alcoholics, illegal drug users or drugs that may interfere in the search results;
• Diagnosis of cardiorespiratory and metabolic disease;
• Absence of ischemic and conduction ECG alterations at rest or during the clinical exercise test;
• Body mass index (BMI) <30 kg/m²;
• Presence of respiratory muscle weakness [maximal inspiratory pressure (MIP <60% predicted);
• Alterations in the pulmonary function test (PFT) or other test;
• Have performed of inspiratory muscle training in the last six months.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Performance in exercise evaluated by measurement the maximal or peak comsumption the oxygen (VO2max or peak)	Three years	The performance will be evaluated by measurement the maximal or peak comsumption the oxygen (VO2max or peak), determinated by the cardiopulmonary exercise testing.
Performance in exercise evaluated by measurement the work load (W)	Three years	The performance will be evaluated by measurement the work load (W), determinated by the cardiopulmonary exercise testing.; The evaluation will realize before, fifth and ninth weeks and after the training.

Secondary Outcome Measures

Name	Time	Method
Metaboreflex activation to inspiratory muscle training	Three years	To evaluate if the IMT, using PThC, changes the intensity of the metaboreflex activation, evaluated during the cardiopulmonary exercise testing and the progressive inspiratory threshold-loading test.; The evaluation will realize before, fifth and ninth weeks and after the training.
Metabolic responses to inspiratory muscle training	Three years	The oxyhemoglobin, deoxyhemoglobin and total hemoglobin responses will be measured by near-infrared spectroscopy (NIRS) (Oxymon MKIII), during cardiopulmonary exercise test and progressive inspiratory threshold-loading test.; The evaluation will realize before, fifth and ninth weeks and after the training.
Cardiovascular responses to inspiratory muscle training	Three years	The cardiovascular responses \[systolic arterial pressure (PAS), dyastolic arterial pressure (PAD), using Finometer PRO; and heart rate, using BioAmp FE132\] will be evaluated during the cardiopulmonary exercise testing and progressive inspiratory threshold-loading test, .; The evaluation will realize before, fifth and ninth weeks and after the training.
Respiratory responses to inspiratory muscle training	Three years	The ventilatory parameters \[carbon dioxide production (VCO₂), respiratory exchange rate (RER), lung ventilation (VE), oxygen uptake efficiency slope (OUES), minute ventilation-carbon dioxide production slope (VE/VCO₂slope)\] will monitored and registered breath-by-breath using a ventilatory-metabolic system ULTIMA/Breeze Suite 7.2., during cardiopulmonary exercise test and progressive inspiratory threshold-loading test.; The evaluation will realize before, fifth and ninth weeks and after the training.
Autonomic responses to inspiratory muscle training	Three years	The cardiovascular autonomic tests, heart rate variability (HRV) and blood pressure variability (BPV), at rest and after active postural change will realize before and after the training.; The ECG (BioAmp FE132), blood pressure (BP), using Finometer Pro (Finapress Medical Systems) and respiration (Marazza) signals will be acquired. The signals will be coupled by data acquisition and analysis device (Power Lab 8/35) and sampled at 1000 Hz.

Trial Locations

Locations (1)

Federal University of Sao Carlos; 🇧🇷 Sao Carlos, Sao Paulo, Brazil