Respiratory muscle training represents an effective method increasingly utilized in both sports and healthcare domains, employing various devices, among which threshold devices are prominent. The aim of this study is to determine the relationship between inspiratory muscle fatigue and maximal inspiratory pressure, diaphragmatic strength (guided by ultrasound image) and heart rate variability. According to our hypothesis, the execution of a protocol inducing inspiratory muscle fatigue in older adults could influence cardiorespiratory function. In this study, subjects will be divided into three groups: the experimental group , the activation group and the control group. Measurements of variables, such as maximal inspiratory pressure, heart rate variability and diaphragmatic strength (ultrasound image), will be conducted.
This is a randomized control trial. The experimental group (EG) will perform the diaphragmatic fatigue protocol using a specific inspiratory endurance test, in which volunteers, one-on-one, and in a single session, will breathe against submaximal inspiratory loads equivalent to 60% of their Maximum Inspiratory Pressure (MIP) through a threshold valve device. The participants will follow a free pattern of breathing until they are unable to establish flow during at least 3 maximum inspiratory efforts. The activation group (AG) will perform the protocol of 2 sets of 30 repetitions at 15% of their MIP, one-on-one, and in a single session, using a threshold valve device. The control group will do a seat and wait. The interventions will be supervised by a physiotherapist. The primary outcomes will be Respiratory muscle strength will be assessed using a respiratory pressure meter or manometer designed, and with ultrasound image measuring the cross sectional area of the diaphragm at 8-9th rib level and speed of contraction with a deep and fast inspiratory manoeuver. This will be done immediately before intervention and immediately after intervention Heart rate variability (HRV) will be assessed using a heart rate sensor Polar H10.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
18
The subjects will perform deep inspirations against a threshold device with varying resistances,
Respiratory muscle strength
It will be assessed using a MicroRPM® (MicroMedical, UK).The MicroRPM® is likely a respiratory pressure meter or manometer designed for measuring respiratory muscle strength. It typically includes a mouthpiece connected to a pressure sensor, and the device measures the force or pressure generated during respiratory maneuvers. The person will be instructed to take a maximal deep breath in, and then exhale to residual volume. After that, they will be asked to inhale forcefully against the resistance provided by the MicroRPM®. This measures the strength of the inspiratory muscles. The measures will be expressed in cmH2O.
Time frame: Pre intervention and immediately post intervention
Diaphragmatic thickness and thickening fraction
Diaphragmatic thickness and thickening fraction The linear array probe with a frequency of 3.0-10 megahertz (MHz) is placed perpendicularly to chest wall close to the mid-axillary line which is between the 8th and 10th intercostal space. The thickness of diaphragm is measured at the end of expiration and maximum inspiration for three times and the average values were recorded. The measures will be expressed in centimeters.
Time frame: Pre intervention and immediately post intervention
Diaphragm movement curve
The convex array probe with a frequency of 1.5-4.6 MHz is placed below the midclavicular line of the right costal margin in longitudinal scanning plane. The liver was used as an inspection window, and the probe was pointed toward the cephalic side. The ultrasound bundle is perpendicular to the posterior third of the right diaphragm. M-mode ultrasound is used to record the diaphragmatic movement curve during quiet breathing (QB) and deep breathing (DB). The measures will be expressed in seconds.
Time frame: Pre intervention and immediately post intervention
Heart rate variability
The analysis of Heart Rate Variability will be conducted using a heart rate monitor. Cardiac electrical signals will be monitored with a band placed on the chest for 5 minutes with the subject in supine position on a stretcher, in a quiet environment, soft light, and a comfortable temperature. Subjects are instructed not to speak or make voluntary movements during this analysis.
Time frame: Pre intervention and immediately post intervention
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