Respiratory Muscle FunctionNCT07717801
Effects of Diaphragmatic Breathing Retraining in Combat Sport Athletes With Dysfunctional Breathing Patterns
A study testing Diaphragmatic breathing training exercise and Usual training in people with Respiratory Muscle Function and Athletic Performance, run by National Cheng Kung University at 1 site in Taiwan.
Trial summary
Combat sport athletes often need to maintain a guarded posture, stabilize the trunk, react quickly, and control balance during contact or unexpected movement. These demands may be related not only to strength and conditioning, but also to the coordination between breathing and postural control. Read more about this study
- Who is it for?
- Ages 18 to 50 years
- Conditions the study is for
- Respiratory Muscle Function, Athletic Performance, Postural Balance
- What is being tested?
- Diaphragmatic breathing training exercise and Usual training
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteTaiwan
- Study dates
- 1 May 2026to Jul 2029
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 50 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Aged between 18 and 50 years.
- Currently participating regularly in combat sports, such as taekwondo, boxing, judo, karate, jiu-jitsu, or similar sports, with at least 2 years of training experience.
- Training at least 3 times per week.
Who cannot join
- Current or major musculoskeletal injury within the past year that may affect testing or training performance.
- History of major thoracic, abdominal, or spinal surgery.
- Known cardiopulmonary diseases, such as asthma, chronic obstructive pulmonary disease, or heart disease; neurological disorders; vestibular dysfunction; or other conditions that may affect balance.
- Current or recent pregnancy.
- Previous participation in breathing training or respiratory therapy, or current use of medications that may affect respiratory or neuromuscular function.
- Inability to complete ultrasound assessment, motion analysis, or exercise testing.
- Having a subordinate relationship or conflict of interest with the principal investigator or co-investigators, such as being a supervised student, research assistant, employee, or other related personnel.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Taiwan1 site, 1 recruiting
- Recruiting
Department of Physical Therapy, National Cheng Kung University,
Tainan, 701
Chiao-Yun Lin, +886-6-2353535 ext. 5930, qlin0101@gmail.com
About this study
Official title: Dysfunctional Breathing Patterns, Diaphragmatic Function, Core Stability, and Postural Control in Combat Sport Athletes: Diaphragm-Centered Neuromuscular Control Perspective and Effects of Diaphragmatic Breathing Retraining
Combat sport athletes often need to maintain a guarded posture, stabilize the trunk, react quickly, and control balance during contact or unexpected movement. These demands may be related not only to strength and conditioning, but also to the coordination between breathing and postural control. The diaphragm is the main muscle for breathing and also contributes to trunk stability through its role in pressure regulation and deep core control. However, dysfunctional breathing patterns, such as upper-chest dominant breathing, reduced lower rib expansion, or poor coordination between the chest and abdomen, may interfere with this function.
The purpose of this study is to examine dysfunctional breathing patterns in combat sport athletes and to investigate whether diaphragmatic breathing retraining can improve breathing patterns, diaphragm function, core stability, postural control, and sport-related performance. This study will first screen athletes from combat and non-combat sports to determine the prevalence of dysfunctional breathing. Combat sport athletes will then complete laboratory tests to examine the relationship between breathing pattern, posture, diaphragm function, core stability, and postural control. In the intervention part of the study, combat sport athletes with dysfunctional breathing will be randomly assigned to diaphragmatic breathing retraining plus usual training or usual training only. The study will compare the two groups to determine whether adding diaphragmatic breathing retraining provides additional benefits. The study will also examine whether the changes are maintained after training and whether baseline measures can help identify athletes who respond better to the program.
Read the detailed description
Combat sports place high demands on the neuromuscular system. Athletes must generate force, absorb impact, maintain balance, and respond to an opponent under rapidly changing conditions. Many combat sport athletes also use protective or guarded postures during training and competition. These postures may help with short-term stability, but they may also be associated with altered trunk control, reduced movement adaptability, and increased loading on the spine and surrounding tissues.
Breathing mechanics may be one factor related to these movement-control demands. The diaphragm is not only the primary muscle for inspiration, but also contributes to trunk stabilization. Through its interaction with the abdominal wall, pelvic floor, and deep spinal muscles, the diaphragm helps regulate intra-abdominal pressure and support postural control. When breathing is dominated by the upper chest or accessory muscles, the coordination between breathing and trunk stabilization may be less efficient.
Dysfunctional breathing has been reported in physically active and athletic populations, but its role in combat sport athletes is still not well understood. Most sport-related breathing studies have focused on respiratory muscle strength or endurance. Less attention has been given to breathing pattern normalization and the integration of breathing with postural control. For this reason, the present study focuses on dysfunctional breathing as a possible neuromuscular control issue rather than only a respiratory problem.
This study includes three main stages. In the first stage, athletes from combat and non-combat sports will be screened for dysfunctional breathing and postural characteristics. This stage will estimate the prevalence of dysfunctional breathing and compare breathing patterns between sport types. A subgroup of combat sport athletes will also complete laboratory-based testing to examine whether breathing pattern is associated with diaphragm function, posture, core stability, and postural control.
In the second stage, combat sport athletes with dysfunctional breathing will participate in an intervention study. Participants will first complete a single-session breathing correction assessment to examine immediate changes in breathing pattern and diaphragm function. They will then be randomly assigned to either diaphragmatic breathing retraining plus usual training or usual training only. The breathing retraining program will last 8 weeks and will progress from breathing correction in supported positions to breathing control in upright and core-demanding positions.
Assessments will be performed before the intervention, after the first breathing correction session, after the 8-week intervention, and at follow-up. The assessments will include breathing pattern evaluation, ultrasound assessment of diaphragm function, respiratory muscle strength testing, movement analysis, force plate testing, muscle activity recording, and functional sport performance tests. These tests are used to examine whether changes in breathing are accompanied by changes in trunk control, balance responses, and sport-related function.
In the third stage, the study will explore why some athletes improve more than others. Athletes who receive diaphragmatic breathing retraining will be classified as responders or non-responders based on changes in breathing pattern. Baseline breathing severity, diaphragm function, posture, core stability, postural control, and low back pain status will be examined as possible factors related to training response.
Overall, this study aims to clarify the relationship between breathing pattern and movement control in combat sport athletes. The findings may help determine whether diaphragmatic breathing retraining can be used as a practical strategy to improve breathing control, trunk stability, postural control, and sport-related performance in athletes with dysfunctional breathing.
- Being tested
- Diaphragmatic breathing training exercise, Usual training
- Keywords
- Combat sport athletes, Dysfunctional breathing, Diaphragmatic function, Diaphragmatic breathing retraining, Core stability, Postural control
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Diaphragmatic breathing training exerciseOther
Participants will complete one session of diaphragmatic breathing correction. During the session, verbal instruction, manual facilitation, and corrective feedback will be used to guide participants toward a more diaphragmatic breathing pattern. Participants will be instructed to breathe with relaxed shoulders and neck, increase lower rib cage and abdominal expansion, and minimize upper-chest dominant breathing. The intervention is designed to examine the immediate effects of breathing correction on breathing pattern characteristics, diaphragm function, postural alignment, and core stability-related outcomes.
Usual trainingOther
Participants continue their regular sport-specific training schedule. They receive non-specific limb stretching and general exercise education but no structured breathing exercises or breathing instruction during the study period.
| Study group | Role | What they receive |
|---|---|---|
| Diaphragmatic Breathing Retraining Group | Experimental | Combat sport athletes with dysfunctional breathing patterns will receive supervised diaphragmatic breathing training. Receives: Other: Diaphragmatic breathing training exercise |
| Usual Training Control Group | Other | Combat sport athletes in the control group will continue their usual sport-specific training without any structured breathing intervention. They will receive non-specific limb stretching and general exercise education. Receives: Other: Usual training |
What is being measured
The primary outcome is the main question the study is designed to answer.
Breathing Pattern_ Total Faulty Breathing Scale (TFBS) Score
Breathing pattern severity assessed using the Total Faulty Breathing Scale (TFBS), a structured observational tool scored 0-12. Higher scores indicate greater breathing dysfunction. Assessed during 10 cycles of quiet and 10 cycles of deep breathing in standing. Also supported by Manual Assessment of Respiratory Motion (MARM).
Measured: Baseline (Day 1), Day 1 (immediately after first session), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Trunk Flexor Endurance _ McGill Curl-Up Hold Test
Description: Isometric trunk flexor endurance measured as hold time during the McGill Curl-Up Test. A longer time indicates greater endurance.
Unit of Measure: seconds
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Back Extensor Endurance _Biering-Sørensen Test
Isometric back extensor endurance measured as hold time during the Biering-Sørensen Test. A longer time indicates greater endurance.
Unit of Measure: seconds
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Movement Speed_10-Meter Sprint Time
Time to complete a 10-meter maximal sprint from a combat/two-point stance, measured with electronic timing gates. Lower time indicates better performance.
Unit of Measure: seconds
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Agility _ T-Test Time
Time to complete the agility T-test course (sprint forward, lateral shuffles, backward run around 4 cones in a T-shape). Lower time indicates better multidirectional agility.
Unit of Measure: seconds
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Visual Motor Reaction Time _ BlazePod System
Average reaction time to randomly illuminated light pods during a standardized protocol from a fighting stance, using the BlazePod system (BlazePod Ltd.). Lower time indicates faster reaction.
Unit of Measure: milliseconds
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Dynamic Balance _ Y Balance Test Composite Score
Maximum normalized reach distance in the anterior, posteromedial, and posterolateral directions during single-leg stance on the Y-Balance Test.
Unit of Measure: percent of leg length
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Reactive Postural Control - Time to Stabilization
Time to stabilization of center of pressure after an unexpected anterior pulling perturbation (10% body weight), measured via force plate. Lower time indicates better reactive postural control. Unit of Measure: seconds
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Reactive Postural Control - Trunk/Pelvis Angular Displacement
Angular displacement of the trunk and pelvis during the stabilization phase following an unexpected anterior pulling perturbation, measured via 3D motion capture. Unit of Measure: degrees
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Reactive Postural Control - Trunk/Pelvis Angular Velocity
Angular velocity of the trunk and pelvis during the stabilization phase following an unexpected anterior pulling perturbation, measured via 3D motion capture. Unit of Measure: degrees per second
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Reactive Postural Control - Peak Ground Reaction Force
Peak ground reaction force during the stabilization phase following an unexpected anterior pulling perturbation, measured via force plate. Unit of Measure: percent of body weight
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Reactive Postural Control - COP Path Length
Total center-of-pressure trajectory length during the stabilization phase following an unexpected anterior pulling perturbation, measured via force plate and normalized to foot length. Unit of Measure: mm
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Reactive Postural Control - Trunk Muscle Onset Latency
EMG onset latency of trunk muscles relative to perturbation onset, measured via surface electromyography. Unit of Measure: milliseconds
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Reactive Postural Control - Trunk Muscle EMG Amplitude
Normalized EMG amplitude of trunk muscles during the early stabilization phase following an unexpected anterior pulling perturbation. Unit of Measure: percent of MVIC
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Maximal Inspiratory Pressure (MIP)
Global inspiratory muscle strength was measured in cmH₂O using a gas pressure gauge (Galemed Corporation). Participants exhale maximally, then inhale forcefully against the gauge for ≥1 second with a nose clip applied.
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion) Secondary
Maximal Expiratory Pressure (MEP)
Global expiratory muscle strength is measured using a gas pressure gauge. Participants inhale maximally, then exhale forcefully against the gauge for ≥1 second.
Unit of Measure: cmH₂O
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Diaphragmatic Excursion
Maximum diaphragmatic excursion during maximal inspiration and expiration, measured by M-mode ultrasonography with a 1-5 MHz convex transducer in the right mid-clavicular subcostal region.
Unit of Measure: cm
Measured: Baseline (Day 1), Day 1 (immediately after first session), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Diaphragmatic Thickening Fraction
Diaphragmatic thickening fraction calculated from B-mode ultrasound measurements of diaphragm thickness at end-maximal inspiration and end-maximal expiration, using a 4-12 MHz linear transducer at the zone of apposition.
Unit of Measure: percent
Measured: Baseline (Day 1), Day 1 (immediately after first session), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Proactive Core Stability - Time to Stabilization
Time to stabilization of center of pressure after single-leg drop landing, measured via force plate. Lower time indicates better proactive core stability. Unit of Measure: seconds
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Proactive Core Stability - Trunk/Pelvis Angular Displacement
Angular displacement of the trunk and pelvis during the stabilization phase following single-leg drop landing, measured via 3D motion capture. Unit of Measure: degrees
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Proactive Core Stability - Trunk/Pelvis Angular Velocity
Angular velocity of the trunk and pelvis during the stabilization phase following single-leg drop landing, measured via 3D motion capture. Unit of Measure: degrees per second
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Proactive Core Stability - Peak Ground Reaction Force
Peak ground reaction force during the stabilization phase following single-leg drop landing, measured via force plate. Unit of Measure: percent of body weight
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Proactive Core Stability - COP Path Length
Total center-of-pressure trajectory length during the stabilization phase following single-leg drop landing, measured via force plate and normalized to foot length. Unit of Measure: mm
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Proactive Core Stability - Trunk Muscle EMG Amplitude
Normalized EMG amplitude of trunk muscles during the early stabilization phase following single-leg drop landing. Unit of Measure: percent of MVIC
Measured: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jul 2026
- Study start1 May 2026
- Primary completionJul 2029 (estimated)
- Study completionJul 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Respiratory Muscle FunctionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- National Cheng Kung University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, YI-JU TSAI, National Cheng Kung University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07717801
- Sponsor's protocol ID
- NCKU_Combat_Diaphragm
- Status last verified
- Jul 2026
- First submitted
- 2 Jul 2026
- Last updated
- 21 Jul 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 21 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Dysfunctional Breathing Patterns, Diaphragmatic Function, Core Stability, and Postural Control in Combat Sport Athletes: Diaphragm-Centered Neuromuscular Control Perspective and Effects of Diaphragmatic Breathing Retraining
- ClinicalTrials.gov ID
- NCT07717801
- Acronym / sponsor ID
- NCKU_Combat_Diaphragm
- Keywords
- Combat sport athletes, Dysfunctional breathing, Diaphragmatic function, Diaphragmatic breathing retraining, Core stability, Postural control
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- National Cheng Kung UniversityUniversity, hospital or other
- Study start
- 1 May 2026 (actual)
- Primary completion
- Jul 2029 (estimated)
- Study completion
- Jul 2029 (estimated)
- First posted
- 21 Jul 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Combat sport athletes often need to maintain a guarded posture, stabilize the trunk, react quickly, and control balance during contact or unexpected movement. These demands may be related not only to strength and conditioning, but also to the coordination between breathing and postural control. The diaphragm is the main muscle for breathing and also contributes to trunk stability through its role in pressure regulation and deep core control. However, dysfunctional breathing patterns, such as upper-chest dominant breathing, reduced lower rib expansion, or poor coordination between the chest and abdomen, may interfere with this function.
The purpose of this study is to examine dysfunctional breathing patterns in combat sport athletes and to investigate whether diaphragmatic breathing retraining can improve breathing patterns, diaphragm function, core stability, postural control, and sport-related performance. This study will first screen athletes from combat and non-combat sports to determine the prevalence of dysfunctional breathing. Combat sport athletes will then complete laboratory tests to examine the relationship between breathing pattern, posture, diaphragm function, core stability, and postural control. In the intervention part of the study, combat sport athletes with dysfunctional breathing will be randomly assigned to diaphragmatic breathing retraining plus usual training or usual training only. The study will compare the two groups to determine whether adding diaphragmatic breathing retraining provides additional benefits. The study will also examine whether the changes are maintained after training and whether baseline measures can help identify athletes who respond better to the program.
Detailed description
Combat sports place high demands on the neuromuscular system. Athletes must generate force, absorb impact, maintain balance, and respond to an opponent under rapidly changing conditions. Many combat sport athletes also use protective or guarded postures during training and competition. These postures may help with short-term stability, but they may also be associated with altered trunk control, reduced movement adaptability, and increased loading on the spine and surrounding tissues.
Breathing mechanics may be one factor related to these movement-control demands. The diaphragm is not only the primary muscle for inspiration, but also contributes to trunk stabilization. Through its interaction with the abdominal wall, pelvic floor, and deep spinal muscles, the diaphragm helps regulate intra-abdominal pressure and support postural control. When breathing is dominated by the upper chest or accessory muscles, the coordination between breathing and trunk stabilization may be less efficient.
Dysfunctional breathing has been reported in physically active and athletic populations, but its role in combat sport athletes is still not well understood. Most sport-related breathing studies have focused on respiratory muscle strength or endurance. Less attention has been given to breathing pattern normalization and the integration of breathing with postural control. For this reason, the present study focuses on dysfunctional breathing as a possible neuromuscular control issue rather than only a respiratory problem.
This study includes three main stages. In the first stage, athletes from combat and non-combat sports will be screened for dysfunctional breathing and postural characteristics. This stage will estimate the prevalence of dysfunctional breathing and compare breathing patterns between sport types. A subgroup of combat sport athletes will also complete laboratory-based testing to examine whether breathing pattern is associated with diaphragm function, posture, core stability, and postural control.
In the second stage, combat sport athletes with dysfunctional breathing will participate in an intervention study. Participants will first complete a single-session breathing correction assessment to examine immediate changes in breathing pattern and diaphragm function. They will then be randomly assigned to either diaphragmatic breathing retraining plus usual training or usual training only. The breathing retraining program will last 8 weeks and will progress from breathing correction in supported positions to breathing control in upright and core-demanding positions.
Assessments will be performed before the intervention, after the first breathing correction session, after the 8-week intervention, and at follow-up. The assessments will include breathing pattern evaluation, ultrasound assessment of diaphragm function, respiratory muscle strength testing, movement analysis, force plate testing, muscle activity recording, and functional sport performance tests. These tests are used to examine whether changes in breathing are accompanied by changes in trunk control, balance responses, and sport-related function.
In the third stage, the study will explore why some athletes improve more than others. Athletes who receive diaphragmatic breathing retraining will be classified as responders or non-responders based on changes in breathing pattern. Baseline breathing severity, diaphragm function, posture, core stability, postural control, and low back pain status will be examined as possible factors related to training response.
Overall, this study aims to clarify the relationship between breathing pattern and movement control in combat sport athletes. The findings may help determine whether diaphragmatic breathing retraining can be used as a practical strategy to improve breathing control, trunk stability, postural control, and sport-related performance in athletes with dysfunctional breathing.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Diaphragmatic Breathing Retraining Group | Experimental | Other: Diaphragmatic breathing training exerciseCombat sport athletes with dysfunctional breathing patterns will receive supervised diaphragmatic breathing training. |
| Usual Training Control Group | Other | Other: Usual trainingCombat sport athletes in the control group will continue their usual sport-specific training without any structured breathing intervention. They will receive non-specific limb stretching and general exercise education. |
Who may qualify
- Ages
- 18 to 50 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Aged between 18 and 50 years.
- Currently participating regularly in combat sports, such as taekwondo, boxing, judo, karate, jiu-jitsu, or similar sports, with at least 2 years of training experience.
- Training at least 3 times per week.
Key exclusion criteria (7 listed)
- Current or major musculoskeletal injury within the past year that may affect testing or training performance.
- History of major thoracic, abdominal, or spinal surgery.
- Known cardiopulmonary diseases, such as asthma, chronic obstructive pulmonary disease, or heart disease; neurological disorders; vestibular dysfunction; or other conditions that may affect balance.
- Current or recent pregnancy.
- Previous participation in breathing training or respiratory therapy, or current use of medications that may affect respiratory or neuromuscular function.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Diaphragmatic breathing training exerciseParticipants will complete one session of diaphragmatic breathing correction. During the session, verbal instruction, manual facilitation, and corrective feedback will be used to guide participants toward a more diaphragmatic breathing pattern. Participants will be instructed to breathe with relaxed shoulders and neck, increase lower rib cage and abdominal expansion, and minimize upper-chest dominant breathing. The intervention is designed to examine the immediate effects of breathing correction on breathing pattern characteristics, diaphragm function, postural alignment, and core stability-related outcomes. | Other | Diaphragmatic Breathing Retraining Group |
| Usual trainingParticipants continue their regular sport-specific training schedule. They receive non-specific limb stretching and general exercise education but no structured breathing exercises or breathing instruction during the study period. | Other | Usual Training Control Group |
Primary outcome
Breathing Pattern_ Total Faulty Breathing Scale (TFBS) Score
Time frame: Baseline (Day 1), Day 1 (immediately after first session), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Breathing pattern severity assessed using the Total Faulty Breathing Scale (TFBS), a structured observational tool scored 0-12. Higher scores indicate greater breathing dysfunction. Assessed during 10 cycles of quiet and 10 cycles of deep breathing in standing. Also supported by Manual Assessment of Respiratory Motion (MARM).
Trunk Flexor Endurance _ McGill Curl-Up Hold Test
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Description: Isometric trunk flexor endurance measured as hold time during the McGill Curl-Up Test. A longer time indicates greater endurance. Unit of Measure: seconds
Back Extensor Endurance _Biering-Sørensen Test
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Isometric back extensor endurance measured as hold time during the Biering-Sørensen Test. A longer time indicates greater endurance. Unit of Measure: seconds
Movement Speed_10-Meter Sprint Time
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Time to complete a 10-meter maximal sprint from a combat/two-point stance, measured with electronic timing gates. Lower time indicates better performance. Unit of Measure: seconds
Agility _ T-Test Time
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Time to complete the agility T-test course (sprint forward, lateral shuffles, backward run around 4 cones in a T-shape). Lower time indicates better multidirectional agility. Unit of Measure: seconds
Visual Motor Reaction Time _ BlazePod System
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Average reaction time to randomly illuminated light pods during a standardized protocol from a fighting stance, using the BlazePod system (BlazePod Ltd.). Lower time indicates faster reaction. Unit of Measure: milliseconds
Dynamic Balance _ Y Balance Test Composite Score
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Maximum normalized reach distance in the anterior, posteromedial, and posterolateral directions during single-leg stance on the Y-Balance Test. Unit of Measure: percent of leg length
Reactive Postural Control - Time to Stabilization
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Time to stabilization of center of pressure after an unexpected anterior pulling perturbation (10% body weight), measured via force plate. Lower time indicates better reactive postural control. Unit of Measure: seconds
Reactive Postural Control - Trunk/Pelvis Angular Displacement
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Angular displacement of the trunk and pelvis during the stabilization phase following an unexpected anterior pulling perturbation, measured via 3D motion capture. Unit of Measure: degrees
Reactive Postural Control - Trunk/Pelvis Angular Velocity
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Angular velocity of the trunk and pelvis during the stabilization phase following an unexpected anterior pulling perturbation, measured via 3D motion capture. Unit of Measure: degrees per second
Reactive Postural Control - Peak Ground Reaction Force
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Peak ground reaction force during the stabilization phase following an unexpected anterior pulling perturbation, measured via force plate. Unit of Measure: percent of body weight
Reactive Postural Control - COP Path Length
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Total center-of-pressure trajectory length during the stabilization phase following an unexpected anterior pulling perturbation, measured via force plate and normalized to foot length. Unit of Measure: mm
Reactive Postural Control - Trunk Muscle Onset Latency
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
EMG onset latency of trunk muscles relative to perturbation onset, measured via surface electromyography. Unit of Measure: milliseconds
Reactive Postural Control - Trunk Muscle EMG Amplitude
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Normalized EMG amplitude of trunk muscles during the early stabilization phase following an unexpected anterior pulling perturbation. Unit of Measure: percent of MVIC
Maximal Inspiratory Pressure (MIP)
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion) Secondary
Global inspiratory muscle strength was measured in cmH₂O using a gas pressure gauge (Galemed Corporation). Participants exhale maximally, then inhale forcefully against the gauge for ≥1 second with a nose clip applied.
Maximal Expiratory Pressure (MEP)
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Global expiratory muscle strength is measured using a gas pressure gauge. Participants inhale maximally, then exhale forcefully against the gauge for ≥1 second. Unit of Measure: cmH₂O
Diaphragmatic Excursion
Time frame: Baseline (Day 1), Day 1 (immediately after first session), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Maximum diaphragmatic excursion during maximal inspiration and expiration, measured by M-mode ultrasonography with a 1-5 MHz convex transducer in the right mid-clavicular subcostal region. Unit of Measure: cm
Diaphragmatic Thickening Fraction
Time frame: Baseline (Day 1), Day 1 (immediately after first session), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Diaphragmatic thickening fraction calculated from B-mode ultrasound measurements of diaphragm thickness at end-maximal inspiration and end-maximal expiration, using a 4-12 MHz linear transducer at the zone of apposition. Unit of Measure: percent
Proactive Core Stability - Time to Stabilization
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Time to stabilization of center of pressure after single-leg drop landing, measured via force plate. Lower time indicates better proactive core stability. Unit of Measure: seconds
Proactive Core Stability - Trunk/Pelvis Angular Displacement
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Angular displacement of the trunk and pelvis during the stabilization phase following single-leg drop landing, measured via 3D motion capture. Unit of Measure: degrees
Proactive Core Stability - Trunk/Pelvis Angular Velocity
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Angular velocity of the trunk and pelvis during the stabilization phase following single-leg drop landing, measured via 3D motion capture. Unit of Measure: degrees per second
Proactive Core Stability - Peak Ground Reaction Force
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Peak ground reaction force during the stabilization phase following single-leg drop landing, measured via force plate. Unit of Measure: percent of body weight
Proactive Core Stability - COP Path Length
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Total center-of-pressure trajectory length during the stabilization phase following single-leg drop landing, measured via force plate and normalized to foot length. Unit of Measure: mm
Proactive Core Stability - Trunk Muscle EMG Amplitude
Time frame: Baseline (Day 1), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)
Normalized EMG amplitude of trunk muscles during the early stabilization phase following single-leg drop landing. Unit of Measure: percent of MVIC
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 21 Jul 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Diaphragmatic breathing training exercise and Usual training in people with Respiratory Muscle Function and Athletic Performance, run by National Cheng Kung University at 1 site in Taiwan.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 21 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Taiwan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Yi-Ju Tsai (+886-6-2353535 ext. 5021, lulilutsai@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Breathing Pattern_ Total Faulty Breathing Scale (TFBS) Score (time frame: Baseline (Day 1), Day 1 (immediately after first session), Week 8 (post-intervention), Week 16 (8 weeks after intervention completion)). The study lists 24 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 21 Jul 2026.