Clinical trial NCT06347549: The Impact of Diaphragmatic Breathing Instructions and Inspiratory Pressures on Diaphragm Contraction in Healthy Adults
Official title: Diaphragmatic and Sternocleidomastoid Muscle Recruitment at Various Inspiratory Loads With and Without Breathing Instruction in Healthy Adults
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Diaphragm
Keywords: Diaphragmatic thickening fraction
Sternocleidomastoid muscles
Inspiratory pressures
Lead sponsor: Hong Kong Metropolitan University
Sponsor class: OTHER
First posted: 2024-04-04
Enrollment: 62
Sex: ALL
Minimum age (years): 18
Maximum age (years): 80
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: CASE_CROSSOVER
Time perspective: CROSS_SECTIONAL
Sampling method: PROBABILITY_SAMPLE
Study population: Healthy adults

Brief summary: 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.

Detailed description: 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.

Eligibility criteria: 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.

Primary outcomes:
measure: Diaphragmatic thickening fraction
timeFrame: Through study completion, an average of 1 year
Secondary outcomes:
measure: Muscle activation of the sternocleidomastoid muscle
timeFrame: Through study completion, an average of 1 year
measure: Perceived Exertion Borg scale
timeFrame: Through study completion, an average of 1 year
Other outcomes:
Locations:
city: Hong Kong
country: China
facility: Hong Kong Metropolitan University
state: None Selected
Study officials:
affiliation: Hong Kong Metropolitan University
name: William Tsang
role: PRINCIPAL_INVESTIGATOR
References: