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Completed

NCT Number: NCT06347549

The Impact of Diaphragmatic Breathing Instructions and Inspiratory Pressures on Diaphragm Contraction in Healthy Adults

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.

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Key information

Conditions

Diaphragm

Age range

18 year–80 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Hong Kong Metropolitan University

Hong Kong, None Selected, China

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Participants ≥18 years of age with normal health

Exclusion criteria

  • Pregnancy.
  • Participants with known cardiovascular, pulmonary, musculoskeletal or psychiatric disorders.
  • Participants with respiratory symptoms (from flu or other respiratory infection during the 2 weeks prior to measurements.
  • Participants can not cooperate the maximal inspiratory pressure measurement.

Treatment and study plan

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.

Primary outcomes

  1. Diaphragmatic thickening fraction

    Time frame: Through study completion, an average of 1 year

    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.

Secondary outcomes

  1. Muscle activation of the sternocleidomastoid muscle

    Time frame: Through study completion, an average of 1 year

    Surface electromyography will be used to measure accessory inspiratory muscle (sternocleidomastoid muscles) activity during each inspiratory muscle training intensity.

  2. Perceived Exertion Borg scale

    Time frame: Through study completion, an average of 1 year

    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.

Sponsors and collaborators

Lead sponsor

Hong Kong Metropolitan University

Other

Registry information

Official study title

Diaphragmatic and Sternocleidomastoid Muscle Recruitment at Various Inspiratory Loads With and Without Breathing Instruction in Healthy Adults

Important dates

Study start
2024
Primary completion
2024
Study completion
2024
First posted
Apr 4, 2024
Registry last updated
Jan 28, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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