Abstract
ObjectivesThe aim of this study was to evaluate the acute effects of different inspiratory loads and different interfaces on the breathing pattern and activity of the respiratory muscles.MethodsTwenty healthy adults were recruited and assigned to two groups (20 and 40% of the Maximal Inspiratory Pressure) by way of randomized crossover allocation. Subjects were evaluated during quiet breathing, breathing against inspiratory load, and recovery. The measurements were repeated using two different interfaces (nasal and oral). Chest wall volumes and respiratory muscle activity were assessed with optoelectronic plethysmography and surface electromyography, respectively.ResultsDuring the application of inspiratory load, significant changes were observed in the respiratory rate (p < 0.04), inspiratory time (p < 0.02), minute ventilation (p < 0.04), tidal volume (p < 0.01), end-inspiratory volume (p < 0.04), end-expiratory volume (p < 0.03), and in the activity of the scalene, sternocleiomastoid, and parasternal portion of the intercostal muscles (RMS values, p < 0.01) when compared to quiet breathing, regardless of the load level or the interface applied. Inspiratory load application yielded significant differences between using nasal and oral interfaces with an increase in the tidal volume (p < 0.01), end-inspiratory volume (p < 0.01), and electrical activity of the scalene and sternocleiomastoid muscles (p < 0.01) seen with using the nasal interface.ConclusionThe addition of an inspiratory load has a significant effect on the breathing pattern and respiratory muscle electrical activity, and the effects are greater when the nasal interface is applied.
Highlights
The application of an inspiratory load is a method used for inspiratory muscle training (IMT) (Hostettler et al, 2011); it helps to increase endurance and respiratory muscle strength in order to improve lung function (Sasaki, 2007), functional capacity (Shakouri et al, 2015), and efficacy in bronchial airway clearance (Oliveira et al, 2009)
This study indicates that applied inspiratory loads using a nasal interface could induce compensatory mechanisms in the activities of respiratory muscles, resulting in an improved breathing pattern
The addition of inspiratory loads resulted in: (1) increased tidal volume due to changes in the end-inspiratory volume and end-expiratory volume, the former occurring due to its increase in the RCp and rib cage (RCa) compartments, and the latter by its decrease in the abdomen compartment; (2) these changes were followed by increased electrical activity of the SCL, SCM and intercostal muscle (IC) muscles; (3) these effects were more evident when using the nasal interface
Summary
The application of an inspiratory load is a method used for inspiratory muscle training (IMT) (Hostettler et al, 2011); it helps to increase endurance and respiratory muscle strength in order to improve lung function (Sasaki, 2007), functional capacity (Shakouri et al, 2015), and efficacy in bronchial airway clearance (Oliveira et al, 2009). In inspiratory flow resistance devices, subjects perform inspirations through an orifice of variable diameter; the smaller the orifice diameter, the greater the resistive inspiratory load. These devices depend on the inspiratory flow generated by the subject. The new generation of electronic devices have overcome this limitation, in that, they are based on an electronically controlled variable flow resistive load. It has been reported that its use produces higher training loads and better inspiratory function when compared to pressure threshold devices (Langer et al, 2015). Few studies have evaluated the compensatory mechanisms employed by the respiratory system when breathing is done against electronically controlled variable flow resistive loads
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
