The aim of this clinical study is to determine whether diaphragm-focused IMT training has an effect on respiratory, psychosocial, and cardiovascular parameters in healthy women. The primary questions the study aims to address are as follows: Does Diaphragm-Focused Respiratory Muscle Training (IMT) positively affect participants' psychosocial parameters (attention, anxiety, motivation)? Does Diaphragm-Focused Respiratory Muscle Training (IMT) improve participants' cardiovascular and respiratory parameters? To assess the effects of Diaphragm-Focused IMT on psychosocial, respiratory, and cardiovascular outcomes, participants were administered IMT at 0% of their MIP level, and the results were compared to a SHAM (placebo) group. Participants: They were divided into 3 groups (experimental, SHAM, control); The experimental and SHAM groups received one week of diaphragm muscle activation training before the experimental intervention began, followed by IMT administered five days a week for four weeks. The control group did not participate in any training and only took part in measurements. All measurements were conducted in two phases-pre-test and post-test-under controlled laboratory conditions.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
28
IMT was performed five days a week for four weeks in the experimental groups. The experimental group performed resistance breathing exercises at 40% of their individual MIP values using the PowerBreathe (POWERBreathe International Ltd., Southam, UK) respiratory muscle training device. Each session was performed using a standard protocol (30 breaths × 2), consisting of 30 breaths, 1 min of rest, and another 30 breaths. MIP values were remeasured at the beginning of each week, and the training intensity was updated according to individual levels.
IMT was performed five days a week for four weeks in sham groups. The experimental group performed resistance breathing exercises at 0% of their individual MIP values using the PowerBreathe (POWERBreathe International Ltd., Southam, UK) respiratory muscle training device. Each session was performed using a standard protocol (30 breaths × 2), consisting of 30 breaths, 1 min of rest, and another 30 breaths. Thus, the physiological effect was eliminated, and only procedural control was provided.
Gaziantep University, Faculty of Sport Sciences
Gaziantep, Turkey (Türkiye)
Maximal Inspiratory Pressure (MIP)
Maximal Inspiratory Pressure (MIP) will be assessed as an index of inspiratory muscle strength using a calibrated respiratory pressure device in accordance with established guidelines. Measurements will be performed with participants in a seated position while wearing a nose clip. Participants will be instructed to perform maximal inspiratory efforts against an occluded airway starting from residual volume. At least two to three acceptable and reproducible maneuvers (variation ≤10%) will be obtained, and the highest value will be recorded for analysis. Metrics: Centimeters of water pressure (cmH₂O)
Time frame: Baseline( 1 week) and immediately post-intervention( after 4 week)
Maximal Expiratory Pressure (MEP)
Maximal Expiratory Pressure (MEP) will be assessed as an index of expiratory muscle strength using the same calibrated respiratory pressure device under standardized conditions. Participants will perform maximal expiratory efforts against an occluded airway starting from total lung capacity. At least two to three acceptable and reproducible maneuvers (variation ≤10%) will be recorded, and the highest value will be used for analysis. Metrics: Centimeters of water pressure(cmH₂O)
Time frame: Baseline (1 week) and immediately post-intervention( after 4 week)
Forced Vital Capacity (FVC)
Forced Vital Capacity (FVC) will be measured using spirometry according to ATS standards under standardized resting conditions. The highest value from at least two acceptable maneuvers will be recorded. FVC represents the maximal volume of air exhaled forcefully after a full inspiration. Metrics: Liters(L)
Time frame: Baseline (1 week) and immediately post-intervention(after 4 week)
Forced Expiratory Volume in 1 Second (FEV₁)
Forced Expiratory Volume in 1 Second (FEV₁) will be assessed using spirometry in accordance with American Thoracic Society (ATS) standards. Measurements will be performed with participants in a seated position after reaching resting heart rate and oxygen saturation levels. Each participant will complete at least two acceptable maneuvers, and the highest value meeting ATS acceptability criteria will be recorded. FEV₁ reflects the volume of air exhaled during the first second of a forced expiratory maneuver. Metrics: Liters (L)
Time frame: Baseline (1 week) and immediately post-intervention (after 4 week)
Concentration Performance (CP) Score (d2 Attention Test)
Concentration Performance (CP) score will be assessed using the d2 Test of Attention as an index of selective attention and processing accuracy. The test consists of identifying and marking target stimuli under time pressure across multiple lines. CP is calculated as the total number of correctly marked target items minus commission errors (incorrectly marked items). The test will be administered under standardized conditions in a quiet environment, and scoring will follow established guidelines. Metrics: Score
Time frame: Baseline (1 week) and immediately post-intervention( after 4 week)
State Anxiety Score (STAI Form I)
State anxiety will be assessed using the State-Trait Anxiety Inventory (STAI Form I), a validated self-report questionnaire designed to measure transient anxiety levels at a given moment. The instrument consists of 20 items rated on a 4-point Likert scale. Total scores range from 20 to 80, with higher scores indicating greater levels of state anxiety. The questionnaire will be administered under standardized conditions in a quiet environment, and scoring will be conducted standardized guidelines. Metrics: Score (range: 20-80)
Time frame: Baseline( 1 week) and immediately post-intervention( after 4 week)
Trait Anxiety Score (STAI Form II)
Trait anxiety will be assessed using the State-Trait Anxiety Inventory (STAI Form II), which evaluates relatively stable individual differences in anxiety proneness. The scale consists of 20 items rated on a 4-point Likert scale. Total scores range from 20 to 80, with higher scores indicating higher trait anxiety. The questionnaire will be administered and scored standardized procedures. Metrics: Score ( range: 20-80)
Time frame: Baseline (1 week) and immediately post-intervention (after 4 week)
Exercise Motivation Attitude Scale (Score)
Participants' motivation toward exercise is measured using the Exercise Motivation Attitude Scale. The scale consists of 20 items and uses a 7-point Likert-type rating scale. The total score ranges from 20 to 140, with higher scores indicating higher levels of motivation. Metrics: Score (range: 20-140)
Time frame: Baseline (1 week) and immediately post-intervention (after 4 week)
Heart Rate (HR)
Heart rate (HR) will be measured using a validated pulse oximeter under standardized resting conditions. Measurements will be obtained with participants in a seated position after reaching physiological rest. The average of two consecutive readings will be recorded. Heart rate reflects the number of cardiac beats per minute Metrics: Beats per minute (bpm)
Time frame: Baseline (1 week) and immediately post-intervention (after 4 week)
Peak Expiratory Flow (PEF)
Peak Expiratory Flow (PEF) will be assessed via spirometry under standardized conditions. The highest value from acceptable maneuvers will be recorded. PEF represents the maximum flow achieved during a forced expiratory maneuver. Metrics: Liters per second (L/s)
Time frame: Baseline(1 week) and immediately post-intervention(after 4 week)
Forced Expiratory Flow 25-75% (FEF25-75%)
Forced Expiratory Flow at 25-75% of pulmonary volume (FEF25-75%) will be measured using spirometry ATS standards. The highest acceptable value will be used for analysis. This parameter reflects the average expiratory flow during the middle half of the forced vital capacity maneuver. Metrics: Liters per second (L/s)
Time frame: Baseline(1 week) and immediately post-intervention( after 4 week)
Total Number of Items Processed (TN) (d2 attention test)
The Total Number of Items Processed (TN) will be obtained from the d2 Test of Attention and represents the total number of stimuli scanned and processed by the participant within the test period. This parameter reflects processing speed and work pace under time constraints. Metrics: Score
Time frame: Baseline( 1 week) and immediately post- intervention (after 4 week)
Total Number of Items Processed Minus Errors (TN-E)
The Total Number of Items Processed Minus Errors (TN-E) will be calculated by subtracting omission and commission errors from the total number of processed items (TN). This parameter reflects overall task performance by integrating speed and accuracy. Metrics: Score
Time frame: Baseline (1 week) and immediately post-intervention (after 4 week)
Oxygen Saturation (SpO₂)
Peripheral oxygen saturation (SpO₂) will be measured non-invasively using a calibrated pulse oximeter under standardized resting conditions. Participants will be seated and allowed to reach stable resting heart rate prior to measurement. SpO₂ values will be recorded after signal stabilization, and the average of two consecutive readings will be used for analysis. This parameter reflects the percentage of hemoglobin saturated with oxygen in arterial blood. Metrics: Percentage (%)
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Time frame: Baseline (1 week) and immediately post-intervention ( after 4 week)