An observational study in Diaphragm, sponsored by Hong Kong Metropolitan University. Not yet recruiting at 1 site in Hong Kong. Open to participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-06-06.
Sponsored by Hong Kong Metropolitan University · Observational
This is a cross-sectional obsessional study.
This study explores how different sitting conditions affect two important muscles-the diaphragm and the sternocleidomastoid (SCM)-work during breathing exercises. The diaphragm is the main muscle for breathing, while the SCM helps when taking deeper breaths. Understanding how these muscles interact while sitting under various conditions can help improve breathing training techniques.
The study's objectives are (1) to investigate the relationship between diaphragm thickness fraction with 4 different sitting conditions during loaded inspiration among healthy adults and (2) To investigate the relationship between SCM activity with 4 different sitting conditions during loaded inspiration among healthy adults.
This research will conduct healthy adults, who will be instructed to breathe against resistance provided by the IMT while sitting on four different conditions: a regular chair, a soft pad with feet on the ground, a soft pad with feet on two additional soft pads, and a single soft pad with both feet on one pad. By using ultrasound to measure how thick the diaphragm gets and surface electromyography (sEMG) to track SCM activity, the data will be gathered on how these muscles function under different conditions.
The goal is to find out if sitting on unstable surfaces, like soft pads, can enhance diaphragm use compared to a stable chair. These surfaces may change how effectively the diaphragm and SCM work together. This research could lead to better recommendations for inspiratory muscle training (IMT), which helps strengthen these muscles, especially for people with breathing difficulties.
By identifying how posture influences muscle recruitment during breathing exercises, hoping to contribute valuable insights that can improve rehabilitation programs for individuals with respiratory conditions.
Participant information sheets and consent form will be given and explained to participants prior to experiment. To ensure measurement consistency, one standardized assessor will be employed. Demographic data, including age, sex, exercise habit, and smoking history will be recorded. Health-related quality of life will be quantified by SF-12. Participants who score below 50 in PCS or MCS will be excluded from our study.
All eligible participants will undertake a standard spirometry test to obtain forced vital capacity (FVC), forced expiratory volume in one second (FEV1). Spirometry test will be performed 3 times, in accordance with guidelines recommended by the American Thoracic Society. Participants with findings of obstructive or restrictive disorders will be excluded. MIP will be obtained by a threshold device (S1breathe K5) under standard instruction. Before measuring MIP, specific instructions guiding participants to focus on diaphragm breathing will be instructed (one hand positioned on the subcostal region and allow air to go to the lower part of the chest where your hand is placed) to allow participants aware of the use of diaphragm during trials, therefore they can subconsciously deploy the technique in the subsequent trials. Participants will be allowed to perform 3 times (with nose-clip applied), with the best MIP will be recorded. The thickness of right diaphragm and SCM activity at maximum inspiration, maximum expiration, end-tidal inspiration, end-tidal expiration, and MIP were measured by ultrasonography and sEMG respectively.
Participants will then be instructed to perform IMT in different conditions in a randomized order, completing 4 sets 15 breaths, with a rest period of 5 mins between sets. 50% MIP will be calibrated at the POWERbreathe device with respect to each participant prior IMT. During each inspiratory pressure-targeted breath, simultaneous sEMG recording on the right SCM and ultrasonography of right hemi-diaphragm will be conducted. Participants's subjective exertion level will be recorded by Borg's Rate of Perceived Exertion Scale at the end of each set of recordings.
The POWERbreathe device requires 5 breaths to meet the targeted load. Following the manufacturer's instructions, participants will be instructed to perform with a sharp inspiration lasting 1-2s at each breath for reaching the required load. Each participant will be requested to complete 15 breaths, but only the data from 6th to 15th breaths will be included for analysis. The whole duration will take around 90 minutes. Password code will be used to guarantee anonymity and confidentiality for the data obtained.
1,092 studies on the registry are indexed under Respiratory Aspiration; 216 are open to participants now.
This study's planned enrollment of 45 is below the median of 65 across 184 observational studies indexed under Respiratory Aspiration.
Browse Respiratory Aspiration studies →Hong Kong Metropolitan University is the lead sponsor of 56 studies on the registry; 31 are open to participants now.
Counted across the registry records on this site, refreshed daily.
aged 18-35 healthy young adults
Exclusion Criteria:
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.
Time frame: Through study completion, an average of 1 year
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.
Time frame: Through study completion, an average of 1 year
Borg's scale
The Borg scale is widely used for measuring perceived exertion during physical activity. It can gauge how hard individuals are exerting while taking into account the individual's heart rate, breathing effort, and fatigue level. Participant's subjective experience would also gauge the score of the scale. The Borg RPE scale would be used to measure exertion during exercise as it has a high correlation with physiological measurements. It is quantified from 0 to 10, where 0 represents no symptoms, and 10 represents the maximum symptoms.
Time frame: Through study completion, an average of 1 year
The Short Form (12) Health Survey
The SF-12 is a multidimensional generic measure of health-related quality of life which is based on items taken from the SF-36 health survey. It is composed of standardized questionnaires which cover 12 items selected from the SF-36.It includes 8 domains, physical functioning, role-physical, role-emotional, mental health, bodily pain, general health, vitality, and social functioning. It is scored to produce 2 summary scores, the physical and mental health summaries (PCS and MCS). Scores above 50 predict a better-than-average health-related quality of life. Scores below 50 are considered as below-average health.
Time frame: Through study completion, an average of 1 year
Documents are hosted by the registry — open the source record to download them.
Plan to share: Undecided
This study is not yet recruiting, as verified in May 2025. You cannot join it, but the record below documents what was studied.
Get an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
Hong Kong Metropolitan University