Abstract
BackgroundInspiratory muscle training (IMT) has brought great benefits in terms of improving physical performance in healthy individuals. However, there is no consensus regarding the best training load, as in most cases the maximal inspiratory pressure (MIP) is used, mainly the intensity of 60% of MIP. Therefore, prescribing an IMT protocol that takes into account inspiratory muscle strength and endurance may bring additional benefits to the commonly used protocols, since respiratory muscles differ from other muscles because of their greater muscular resistance. Thus, IMT using critical inspiratory pressure (PThC) can be an alternative, as the calculation of PThC considers these characteristics. Therefore, the aim of this study is to propose a new IMT protocol to determine the best training load for recreational cyclists.MethodsThirty recreational cyclists (between 20 and 40 years old) will be randomized into three groups: sham (SG), PThC (CPG) and 60% of MIP, according to age and aerobic functional capacity. All participants will undergo the following evaluations: pulmonary function test (PFT), respiratory muscle strength test (RMS), cardiopulmonary exercise test (CPET), incremental inspiratory muscle endurance test (iIME) (maximal sustained respiratory pressure for 1 min (PThMAX)) and constant load test (CLT) (95%, 100% and 105% of PThMÁX) using a linear load inspiratory resistor (PowerBreathe K5). The PThC will be calculated from the inspiratory muscle endurance time (TLIM) and inspiratory loads of each CLT. The IMT will last 11 weeks (3 times/week and 55 min/session). The session will consist of 5-min warm-up (50% of the training load) and three sets of 15-min breaths (100% of the training load), with a 1-min interval between them. RMS, iIME, CLT and CPET will be performed beforehand, at week 5 and 9 (to adjust the training load) and after training. PFT will be performed before and after training. The data will be analyzed using specific statistical tests (parametric or non-parametric) according to the data distribution and their respective variances. A p value <0.05 will be considered statistically significant.DiscussionsIt is expected that the results of this study will enable the training performed with PThC to be used by health professionals as a new tool to evaluate and prescribe IMT.Trial registrationClinicalTrials.gov, NCT02984189. Registered on 6 December 2016.
Highlights
Inspiratory muscle training (IMT) has brought great benefits in terms of improving physical performance in healthy individuals
Aim The aim of this study is to propose a new methodology to determine the IMT load for recreational cyclists, which promotes better results for physical performance and for cardiovascular, respiratory and metabolic responses compared to traditional methodologies
Most systematic reviews [1, 3, 19, 49] that study the effects of IMT emphasize the need for studies with a controlled and randomized experimental design, following the guidelines of the Consolidated Standards of Reporting Trials (CONSORT) [50], and to establish training parameters that seek to achieve the best results for the population studied
Summary
Inspiratory muscle training (IMT) has brought great benefits in terms of improving physical performance in healthy individuals. New studies need to be carried out aimed at establishing the best load (intensity), duration and frequency of training for healthy active individuals and to promote central and peripheral adaptations, which can help regulate respiratory muscle activity [16]. Among these parameters, the most studied is the training load, but there is still no consensus as to which is the best load to use. As well as RMS, respiratory muscle endurance (RME) should be considered, as together they make up the main characteristics of the respiratory system, and can bring about greater systemic adjustments, leading to an improvement in physical performance as the respiratory muscles stand out from the other muscles due to their great resistance [18]
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