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Not yet recruitingNCT07795905Updated Nov 3, 2026

Abdominal Air-Pressure Resistance Versus Abdominal Weight Training for Improving Diaphragm Function in Healthy Young Adults

An interventional study of Abdominal Air Pressure Resistance Training and Abdominal Weight Training (AWT) in Diaphragm Thickness and Dyspnoea, sponsored by University of Sharjah. Not yet recruiting at 1 site in United Arab Emirates. Open to participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-11-03.

Sponsored by University of Sharjah · Not applicable, Interventional, and Treatment

Updated Nov 3, 2026Now Not yet recruitingNow Recruiting+7 moreGo to Updates ↓
Phase
Not applicable
Study type
Interventional
Enrollment
42
Allocation
Randomized
Ages
18 Years to 35 Years
Sex
All
01

Study summary

This study aims to compare the effects of abdominal air pressure resistance training, abdominal weight training, and breathing exercises on diaphragmatic strength, endurance, and physiological responses in young healthy adults.

Forty-two healthy adults aged 18-35 years will be randomly allocated to one of three groups: abdominal air pressure resistance training, abdominal weight training, or breathing exercises. Participants will complete supervised training sessions three times per week for eight weeks, with standardized breathing cadence, training volume, and therapist contact time across groups.

This trial will provide the first direct comparison of a programmable pneumatic abdominal loading method with traditional abdominal weight loading and standard breathing exercises in healthy young adults. The findings will help determine the relative effectiveness, tolerability, and safety of these interventions for enhancing diaphragmatic function. The results may contribute to the development of evidence-based respiratory muscle training strategies for rehabilitation, health promotion, and performance enhancement.

02

Conditions studied

  • Diaphragm Thickness
  • Dyspnoea

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Keywords

  • Cardiopulmonary rehabilitation
  • Diaphragm thickness
  • Respiratory muscle
  • Dyspnea
03

In context

Dyspnea

894 studies on the registry are indexed under Dyspnea; 189 are open to participants now.

This study's planned enrollment of 42 is below the median of 50 across 587 interventional studies indexed under Dyspnea.

Browse Dyspnea studies →

Lead sponsor

University of Sharjah is the lead sponsor of 42 studies on the registry; 17 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 35 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • males and females with a (BMI) between 18.5 and 29.9 kg/m²
  • non-smokers
  • have not participated in structured respiratory muscle training within the previous six months
  • able to understand the study procedures
  • provide written .

Exclusion criteria

Exclusion Criteria:

  • have a known cardiopulmonary, neuromuscular, or significant metabolic disease
  • experience a respiratory infection or respiratory symptoms within the preceding 2-3 weeks
  • pregnant
  • have undergone major abdominal or thoracic surgery within the previous six months
  • have uncontrolled hypertension, significant gastroesophageal reflux disease (GERD), or any other condition that could make abdominal loading unsafe, as determined during the screening process.
Terms in these criteria, in plain language(2)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

BMI (body mass index)

Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.

What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

05

Study design

Phase
Not applicable
Primary purpose
Treatment
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Single (Outcomes assessor)
Enrollment
42 participants (estimated)

Study arms

  • Experimental
    Abdominal Air Pressure Resistance Training (AAPR)

    In the AAPR group, resisted diaphragmatic breathing will be performed using a pneumatic abdominal garment or cuff capable of delivering quantifiable air pressure. The abdominal binder was securely fitted around the participant's waist, while the manual sphygmomanometer cuff was positioned vertically over the epigastric region within the abdominal binder. The cuff was inflated to provide external resistance during diaphragmatic breathing. Care was taken to ensure that the cuff and binder did not exert excessive compression over the lower thoracic region or diaphragm, thereby avoiding mechanical restriction of diaphragmatic excursion and allowing participants to maintain their normal, unrestricted diaphragmatic breathing pattern throughout the intervention. Training will begin at a pressure eliciting moderate perceived breathing effort (Borg RPE) or within a predefined range of 5-10 cmH₂O. Pressure will be increased based on Borg exertion level of 5-7, provided symptom and tolerance cri

    Other: Abdominal Air Pressure Resistance Training

  • Active comparator
    Abdominal Weight Training (AWT)

    The AWT group will perform resisted diaphragmatic breathing with a 3-5 kg sandbag positioned over the abdomen while lying in the supine position. Participants will be instructed to perform diaphragmatic breathing, allowing the abdomen to rise during inspiration and fall during expiration while minimizing chest movement. The sandbag load will be individually adjusted for each participant according to a perceived exertion level of 11-13 on the Rating of Perceived Exertion (RPE) scale. Training duration, number of sets and rest periods will be matched with AAPR group to have uniformity across the group.

    Other: Abdominal Weight Training (AWT)

  • Active comparator
    Breathing Exercise Control (BE)

    In the BE control group, standardized diaphragmatic breathing combined with paced slow deep breathing will be performed without the application of external resistance. Training duration, breathing cadence, number of sets, and rest intervals will be matched to those used in the loaded intervention groups. Perceived exertion and symptom responses will be documented during each session

    Other: Breathing Exercise Control (BE)

Interventions

  • OtherAbdominal Air Pressure Resistance Training

    In the AAPR group, resisted diaphragmatic breathing will be performed using a pneumatic abdominal garment or cuff capable of delivering quantifiable air pressure. The abdominal binder was securely fitted around the participant's waist, while the manual sphygmomanometer cuff was positioned vertically over the epigastric region within the abdominal binder. The cuff was inflated to provide external resistance during diaphragmatic breathing. Care was taken to ensure that the cuff and binder did not exert excessive compression over the lower thoracic region or diaphragm, thereby avoiding mechanical restriction of diaphragmatic excursion and allowing participants to maintain their normal, unrestricted diaphragmatic breathing pattern throughout the intervention. Training will begin at a pressure eliciting moderate perceived breathing effort (Borg RPE) or within a predefined range of 5-10 cmH₂O. Pressure will be increased based on Borg exertion level of 5-7.

  • OtherAbdominal Weight Training (AWT)

    In the AWT group, diaphragmatic breathing will be performed with an external load applied to the anterior abdominal wall using a standardized sandbag or weight pack, with participants positioned in supine crook-lying. Load prescription will be implemented using a pre-specified method, which included either a fixed initial load of 2-5 kg with weekly increments of 0.5-1 kg as tolerated, an initial load corresponding to 3-5% of body mass with weekly progression, or load titration based on perceived exertion targeting a Borg RPE of 4-5 during training sets. Training volume, set duration, and rest intervals will be matched to those of the AAPR group. For each session, the load applied, perceived exertion, and symptom responses will be documented.

  • OtherBreathing Exercise Control (BE)

    In the BE control group, standardized diaphragmatic breathing combined with paced slow deep breathing will be performed without the application of external resistance. Training duration, breathing cadence, number of sets, and rest intervals will be matched to those used in the loaded intervention groups. Perceived exertion and symptom responses will be documented during each session.

06

What researchers measure

Primary outcomes

  1. Diaphragm thickening fraction

    Diaphragm thickness will be assessed using a portable ultrasound device (VERSANA PREMIER) operating in B-mode with a 10-MHz linear transducer. Standardized imaging settings, including gain, depth, and focus, were maintained throughout all examinations. Ultrasound measurements were conducted by a trained assessor who was blinded to participants' group assignments. With participants positioned supine, the transducer was placed over the right hemidiaphragm at the zone of apposition, located between the anterior and mid-axillary lines at the eighth to ninth intercostal space. Care was taken to apply minimal pressure with the probe to prevent compression of underlying tissues. Diaphragm thickness measurements were obtained at end-expiration, corresponding to residual volume (RV), and at end-inspiration, corresponding to total lung capacity (TLC). Each measurement was repeated three times with a minimum rest period of 30 seconds between trials, and the mean value was used for analysis.

    Time frame: baseline and at 8 weeks

Secondary outcomes

  1. Maximal inspiratory pressure

    MIP will be measured using a calibrated respiratory pressure manometer in the supported sitting position. Participants will exhale to residual volume and perform maximal inspiration against an occluded airway. At least three maneuvers will be performed with ≥30 seconds rest, and the highest reproducible value will be recorded in cmH₂O.

    Time frame: baseline and at 8 weeks

07

Study locations

1 site
08

References and documents

Individual participant data

Plan to share: No

No publications or documents are linked to this record.

09

Timeline

2 registry updates since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedDate before it movedWhere the date was before it movedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Start is estimated for Nov 2026; primary completion for Mar 2027, 4 months later.

Of 266 non-industry interventional studies with no phase under Dyspnea, half reached primary completion within 13 months of starting (the median), counting those still running; a quarter within 6 and three quarters within 28. This study's planned 4 months is below that.

Counting every sponsor, half of 282 studies reached it within 13 months; a quarter within 6 and three quarters within 28.

Since we started tracking on Sep 25, 2026, the dates moved once, on Nov 3, 2026: start Aug 2026 → Nov 2026, primary completion Nov 2026 → Mar 2027 and completion Nov 2026 → Mar 2027.

Earlier changes are on the record history on ClinicalTrials.gov ↗

How these figures are worked out, and which studies are left out of them.

Registered
Aug 26, 2026
First posted
Aug 31, 2026
StartEst.
Nov 30, 2026was Aug 2026
Primary completionEst.
Mar 30, 2027was Nov 2026
CompletionEst.
Mar 30, 2027was Nov 2026
Last update
Nov 3, 2026
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
Status
Not yet recruiting→Recruiting→Not yet recruiting
changed Oct 13, 2026 · changed Nov 3, 2026
Sites
1 site added — first site in United Arab Emirates
Show site
  • University of Sharjah · Sharjah city, United Arab Emirates
Oct 13, 2026
Start date
Aug 30, 2026→Nov 30, 2026
Nov 3, 2026
Primary completion
Nov 30, 2026→Mar 30, 2027
Nov 3, 2026
Study completion
Nov 30, 2026→Mar 30, 2027
Nov 3, 2026
Primary outcomes
1 time frame changed
What changed in the outcomes
  • Time frameDiaphragm thickening fractionpre and post intervention, 8 weeks → baseline and at 8 weeks
Oct 13, 2026
Secondary outcomes
1 edited
What changed in the outcomes
  • ChangedBefore Modified Borg Rating of Perceived Exertion (RPE) scaleNow Maximal inspiratory pressureTime frame: pre and post intervention, 8 weeks → baseline and at 8 weeks
Oct 13, 2026
Title
Abdominal Air -Pressure Resistance Versus Abdominal Weight Training Versus Breathing Exercise for Improving Diaphragmatic Strength, Endurance, and Physiological ResponsesDiaphragm Function in Healthy Young Healthy Adults: A Study Protocol for RCT
Oct 13, 2026
Show all 2 updates
  1. Nov 3, 2026
    Recruiting→Not yet recruiting
    Start date Aug 30, 2026→Nov 30, 2026
    Primary completion Nov 30, 2026→Mar 30, 2027
    Study completion Nov 30, 2026→Mar 30, 2027
    + 1 other change: site details
  2. Oct 13, 2026
    Not yet recruiting→Recruiting
    1 site added — first site in United Arab Emirates
    Show site
    • University of Sharjah · Sharjah city, United Arab Emirates
    Primary outcomes 1 time frame changed
    What changed in the outcomes
    • Time frameDiaphragm thickening fractionpre and post intervention, 8 weeks → baseline and at 8 weeks
    Secondary outcomes 1 edited
    What changed in the outcomes
    • ChangedBefore Modified Borg Rating of Perceived Exertion (RPE) scaleNow Maximal inspiratory pressureTime frame: pre and post intervention, 8 weeks → baseline and at 8 weeks
    Title Abdominal Air -Pressure Resistance Versus Abdominal Weight Training Versus Breathing Exercise for Improving Diaphragmatic Strength, Endurance, and Physiological ResponsesDiaphragm Function in Healthy Young Healthy Adults: A Study Protocol for RCT
    + 4 other changes: verification date, date precision, responsible party and arm descriptions

From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗

10

Registry details

Key details

Study ID
NCT07795905
Lead sponsor
University of Sharjah
Responsible party
Khushi Patel (Principal investigator, University of Sharjah) — Principal investigator
First posted
Aug 31, 2026
Start date
Nov 30, 2026 (estimated)
Primary completion
Mar 30, 2027 (estimated)
Completion
Mar 30, 2027 (estimated)
Last update
Nov 3, 2026

Study contacts

Kalyana Reddy
Contact
kreddy@sharjah.ac.ae
+971503614889

Oversight

Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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