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This is a cross-sectional obsessional study.
This study aims (1) to investigate the relationship between sternocleidomastoid muscle recruitment and diaphragm thickness fraction during increasing inspiratory resistance in healthy adults; (2) to compare diaphragmatic and sternocleidomastoid muscle recruitment patterns with and without a standard diaphragmatic breathing instruction with increasing inspiratory resistance in healthy adults.
Participants will be asked to breathe through a pressure threshold inspiratory loading device under different inspiratory resistances with and without a standard diaphragmatic breathing instruction. sternocleidomastoid muscle activity will be measured with surface electromyography, and diaphragm thickness will be assessed with ultrasonography.
Upon arrival at the laboratory, eligible participants will first perform a standard spirometry lung function test. The maximum inspiratory pressure (MIP) will be determined with a pressure threshold inspiratory loading device (POWERbreathe, K2). Each participant will then be instructed to use the device to perform, in random order, 10 breaths at an inspiratory intensity of 30%, 40%, 50%, 60%, 70%, and 80% MIP. A rest period of 15 minutes will be allowed between each inspiratory pressure set of 10 breaths. Simultaneous surface electromyographic (sEMG) recording of the right sternocleidomastoid muscle and ultrasound of right diaphragmatic thickness will be conducted during each breath.
The entire recording procedure will be repeated on a separate day. During the repeat measurements, participants will be provided with specific breathing instruction to focus on the use of the diaphragm and to inhale air to the lower part of the chest. Practice trials will be conducted to ensure participant's understanding of diaphragmatic breathing.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Healthy adults | Participants ≥18 years of age with normal health will be recruited in this study. |
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| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Various intensities of inspiratory muscle training | Diagnostic Test | Each participant will be instructed to use a pressure threshold inspiratory loading device to perform, in random order, 10 breaths at an inspiratory intensity of 30%, 40%, 50%, 60%, 70%, and 80% of their maximum inspiratory pressure (MIP). A rest period of 15 minutes will be allowed between each inspiratory pressure set of 10 breaths. Simultaneous surface electromyographic (sEMG) recording of the right sternocleidomastoid muscle and ultrasound of right diaphragmatic thickness will be conducted during each breath. The entire recording procedure will be repeated on a separate day. During the repeat measurements, participants will be provided with specific breathing instruction to focus on the use of the diaphragm and to inhale air to the lower part of the chest. |
| Measure | Description | Time Frame |
|---|---|---|
| Diaphragmatic thickening fraction | Diaphragmatic thickening fraction is determined by "(thickness of the diaphragm at end inspiratory - thickness at end expiratory)/thickness at end expiratory". Diaphragmatic thickness will be measured by ultrasonography. | Through study completion, an average of 1 year |
| Measure | Description | Time Frame |
|---|---|---|
| Muscle activation of the sternocleidomastoid muscle | Surface electromyography will be used to measure accessory inspiratory muscle (sternocleidomastoid muscles) activity during each inspiratory muscle training intensity. | Through study completion, an average of 1 year |
| Perceived Exertion Borg scale |
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Inclusion Criteria:
Exclusion Criteria:
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Healthy adults
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| Name | Affiliation | Role |
|---|---|---|
| William Tsang | Hong Kong Metropolitan University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Hong Kong Metropolitan University | Hong Kong | None Selected | China |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot_SAP | Yes | Yes | No | Study Protocol and Statistical Analysis Plan | Mar 25, 2024 | Mar 28, 2024 | Prot_SAP_000.pdf |
| ICF | No | No | Yes | Informed Consent Form | Mar 25, 2024 | Mar 28, 2024 | ICF_001.pdf |
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|
This is a vertical scale quantified from 0 to 10, where 0 represents no symptoms, and 10 represents the maximum symptoms. The Borg score provides an individual measurement of the exercise intensity. |
| Through study completion, an average of 1 year |