Air Stacking-Assisted Diaphragmatic Breathing in Stroke

Effects of Diaphragmatic Breathing Exercise Using the Air Stacking Technique on Respiratory and Trunk Function in Patients With Stroke: A Randomized Controlled Trial

The purpose of this study is to investigate whether a diaphragmatic breathing exercise using the air stacking technique can improve respiratory function and trunk control in patients with stroke. The experimental group will perform an air stacking-based diaphragmatic breathing exercise using an Ambu-bag, combined with neurodevelopmental treatment, three times per week for 20 minutes over a 4-week period. The control group will receive therapist-guided diaphragmatic breathing exercises with the same frequency and duration, together with the same neurodevelopmental treatment. All participants will be assessed before and after the intervention for pulmonary function, chest wall expansion, and trunk control ability, as well as the Korean version of the Trunk Impairment Scale (K-TIS), the Five Times Sit-to-Stand Test (FTSTS), and the Borg Rating of Perceived Exertion (Borg RPE). Changes between the two groups will be compared to determine the therapeutic effectiveness of the air stacking technique.

Study Overview

• Status: Completed
• Conditions: Stroke; Hemiplegia
• Intervention / Treatment: Behavioral: Air stacking-assisted diaphragmatic breathing; Behavioral: diaphragmatic breathing

Detailed Description

This clinical trial is a randomized controlled study designed to evaluate the effects of a diaphragmatic breathing exercise using the air stacking technique on respiratory and trunk function in patients with stroke. Patients with stroke are prone to respiratory muscle weakness, reduced chest wall expansion, and impaired trunk control, which can limit functional recovery and increase the risk of pulmonary complications. The air stacking technique increases lung volume and chest expansion through consecutive inspirations without exhalation and is known to facilitate more effective breathing and coughing, but its therapeutic effects in patients with stroke have not yet been fully established.

In this study, 20 patients with stroke will be randomly assigned to an experimental group (n = 10) or a control group (n = 10), using blocked randomization to ensure balance between groups. To enhance the objectivity of outcome assessment, all evaluations will be performed by an assessor who is blinded to group allocation. The experimental group will perform an air stacking-based diaphragmatic breathing exercise using an Ambu-bag, three times per week for 20 minutes over a 4-week period, in addition to neurodevelopmental treatment. The control group will receive therapist-guided diaphragmatic breathing exercises with the same frequency and duration, combined with the same neurodevelopmental treatment program. Both groups will receive the interventions for 4 weeks in the same rehabilitation setting.

All participants will undergo assessments before the start of the intervention and after completion of the 4-week program. Outcome measures will include pulmonary function tests (for example, FVC and FEV1), chest wall expansion, and trunk control ability. In addition, trunk function and functional mobility will be evaluated using the Korean version of the Trunk Impairment Scale (K-TIS) and the Five Times Sit-to-Stand Test (FTSTS), and perceived exertion during exercise will be assessed using the Borg Rating of Perceived Exertion (Borg RPE). Pre- to post-intervention changes will be calculated for each participant, and differences in these changes between the experimental and control groups will be analyzed.

The aim of this study is to determine whether a diaphragmatic breathing exercise using the air stacking technique provides additional benefits over conventional diaphragmatic breathing in improving pulmonary function, chest wall expansion, trunk control, and functional performance in patients with stroke. The findings are expected to demonstrate the therapeutic potential and clinical feasibility of an Ambu-bag-assisted air stacking technique and to contribute to the development of more effective respiratory and trunk rehabilitation strategies for individuals with stroke.

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• South Korea
  • Daegu
    • Daegu, Daegu, South Korea, 41199
      • Daegu Fatima Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Inpatients diagnosed with stroke (intracerebral hemorrhage or cerebral infarction) at a general hospital in Daegu, currently receiving physical therapy
• Onset of stroke at least 3 months prior to enrollment
• Spasticity grade of 2 or less on the Modified Ashworth Scale
• No congenital deformity or fracture of the thorax or other orthopedic conditions affecting the chest wall
• No history of pulmonary disease before or after the stroke
• Able to perform respiratory exercises as instructed
• Mini-Mental State Examination-Korean version (MMSE-K) score of 24 or higher, indicating sufficient cognitive ability to understand the study procedures
• Presence of decreased pulmonary function (reduced pulmonary function test parameters) at baseline

Exclusion Criteria:

• Acute stroke status or onset of stroke less than 3 months prior to enrollment
• Severe cardiovascular or respiratory disease that makes participation in respiratory exercise unsafe or impossible
• Cognitive impairment or communication disorder that prevents understanding or performing the study procedures
• Any other medical or safety condition judged by the investigator to make participation in the study inappropriate

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Air stacking-assisted diaphragmatic breathing; articipants in this arm will receive diaphragmatic breathing exercises using the air stacking technique with an Ambu-bag three times per week for 20 minutes over 4 weeks, in addition to routine neurodevelopmental treatment.	Behavioral: Air stacking-assisted diaphragmatic breathing; Diaphragmatic breathing exercise using the air stacking technique with an Ambu-bag, performed three times per week for 20 minutes over 4 weeks, in addition to routine neurodevelopmental treatment.
Active Comparator: diaphragmatic breathing; Participants in this arm will receive diaphragmatic breathing exercises three times per week for 20 minutes over 4 weeks, together with the same neurodevelopmental treatment as the experimental group.	Behavioral: diaphragmatic breathing; diaphragmatic breathing exercise performed three times per week for 20 minutes over 4 weeks, together with the same neurodevelopmental treatment as the experimental group.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Forced Vital Capacity (FVC)	Forced vital capacity (FVC) will be assessed using spirometry at baseline and 4 weeks after the start of the intervention. The outcome measure is the change in FVC from baseline to 4 weeks in each group.	Baseline and 4 weeks after the start of intervention
Change in Forced Expiratory Volume in 1 Second (FEV1)	Forced expiratory volume in 1 second (FEV1) will be assessed using spirometry at baseline and 4 weeks after the start of the intervention. The outcome measure is the change in FEV1 from baseline to 4 weeks in each group.	Baseline and 4 weeks after the start of intervention
Change in FEV1/FVC ratio	The ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) will be assessed using spirometry at baseline and 4 weeks after the start of the intervention. The outcome measure is the change in FEV1/FVC from baseline to 4 weeks in each group.	Baseline and 4 weeks after the start of intervention
Change in Peak Expiratory Flow (PEF)	Peak expiratory flow (PEF) will be assessed using spirometry at baseline and 4 weeks after the start of the intervention. The outcome measure is the change in PEF from baseline to 4 weeks in each group.	Baseline and 4 weeks after the start of intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Trunk Function (Korean Version of the Trunk Impairment Scale, K-TIS)	Trunk function will be assessed using the Korean version of the Trunk Impairment Scale (K-TIS) at baseline and 4 weeks after the start of the intervention. The K-TIS is a clinical scale ranging from 0 to 23, with higher scores indicating better trunk function. The outcome measure is the change in K-TIS total score from baseline to 4 weeks in each group.	Baseline and 4 weeks after the start of intervention
Change in Functional Lower Extremity Performance (Five Times Sit-to-Stand Test, FTSTS)	Functional lower extremity performance will be assessed using the Five Times Sit-to-Stand Test (FTSTS) at baseline and 4 weeks after the start of the intervention. The FTSTS records the time in seconds required to complete five repetitions of rising from and returning to a seated position. Higher times indicate poorer functional performance. The outcome measure is the change in FTSTS completion time from baseline to 4 weeks in each group.	Baseline and 4 weeks after the start of intervention
Change in Perceived Exertion (Borg Rating of Perceived Exertion Scale)	Perceived exertion during breathing exercises will be assessed using the Borg Rating of Perceived Exertion Scale at baseline and 4 weeks after the start of the intervention. The Borg scale ranges from 6 to 20, with higher scores indicating greater perceived exertion. The outcome measure is the change in Borg scale score from baseline to 4 weeks in each group.	Baseline and 4 weeks after the start of intervention

Collaborators and Investigators

• Sponsor: jang ji-hun

Study record dates

Study Major Dates

• Study Start (Actual): September 25, 2025
• Primary Completion (Actual): February 21, 2026
• Study Completion (Actual): February 21, 2026

Study Registration Dates

• First Submitted: April 28, 2026
• First Submitted That Met QC Criteria: May 5, 2026
• First Posted (Actual): May 11, 2026

Study Record Updates

• Last Update Posted (Actual): May 11, 2026
• Last Update Submitted That Met QC Criteria: May 5, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Stroke; Pulmonary function; Hemiplegia; Respiratory rehabilitation; Air stacking; Diaphragmatic breathing; Trunk Impairment Scale; Ambu-bag
• Additional Relevant MeSH Terms: Neurologic Manifestations; Cerebrovascular Disorders; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Vascular Diseases; Cardiovascular Diseases; Paralysis; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Stroke; Hemiplegia
• Other Study ID Numbers: 2025-05-001

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No