Respiratory Muscle TrainingNCT07887282
The Effects of Interval Respiratory Muscle Training on Athletic Performance
A study testing IMT %40 MIP and IMT %50-60-70-80 in people with Respiratory Muscle Training and Inspiratory Muscle Strength, run by Ondokuz Mayıs University at 1 site in Turkey (Türkiye).
Trial summary
This study evaluated the effects of a 4-week respiratory muscle training (RMT) program using constant versus incremental threshold resistance on respiratory muscle strength, pulmonary function, extremity strength, and aerobic/anaerobic endurance in trained athletes. Read more about this study
- Who is it for?
- Ages 18 to 30 years, men onlyHealthy volunteers can take part
- Conditions the study is for
- Respiratory Muscle Training, Inspiratory Muscle Strength, Maximal Oxygen Consumption
- What is being tested?
- IMT %40 MIP and IMT %50-60-70-80
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 23 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 15 Sep 2024to 11 Nov 2024
- Phase
- Interventional
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 30 years
- Men only
- Healthy volunteers accepted
- Adult
Who may be able to join
- Between the ages of 18 and 30,
- Having at least 5 years of active training experience,
- Having a regular training frequency of at least 4 days per week
Who cannot join
- Having a history of lung dysfunction and cardiovascular disease,
- Having had a lower or upper respiratory tract infection within the last four weeks,
- Having a history of smoking,
- Having any ongoing disability
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Faculty of Sport Science
Kahramanmaraş, Onikişubat, 46050
About this study
Official title: The Effects of Interval Respiratory Muscle Training on Functional Performance, Extremity Strength, and Endurance in Athletes
This study evaluated the effects of a 4-week respiratory muscle training (RMT) program using constant versus incremental threshold resistance on respiratory muscle strength, pulmonary function, extremity strength, and aerobic/anaerobic endurance in trained athletes. Participants were randomized into two groups: the Constant IMT group (trained at a fixed 40% of maximal inspiratory pressure [MIP]) and the Incremental IMT group (progressing weekly from 50% to 80% of MIP). Both groups trained twice daily, 5 days per week (2 sets of 30 breaths/day) for 4 weeks. Standardized physiological, spirometric, and athletic performance tests were assessed at baseline and post-intervention.
Read the detailed description
The purpose of this randomized, controlled trial was to compare the physiological and athletic performance adaptations induced by constant versus progressive-load inspiratory muscle training (IMT) in competitive athletes.
Inspiratory muscle fatigue can trigger the respiratory metaboreflex, causing sympathetic vasoconstriction in locomotor muscles and compromising exercise tolerance. Strengthening the inspiratory muscles is hypothesized to attenuate this reflex and improve limb muscular endurance and aerobic capacity.
Participants completed a 4-week intervention with a threshold inspiratory device (PowerBreathe).
- Constant IMT Group: Performed 2 daily sessions (morning and evening) of 30 breaths at a fixed intensity of 40% MIP, 5 days per week.
- Incremental IMT Group: Performed 2 daily sessions of 30 breaths, 5 days per week, starting at 50% MIP in Week 1, and progressing weekly to 60%, 70%, and 80% MIP in Weeks 2, 3, and 4, respectively.
Initial sessions were supervised in the exercise physiology laboratory, with remaining sessions performed under remote video monitoring. Outcomes were evaluated across multiple laboratory visits before and 48 hours following the 4-week protocol.
- Being tested
- IMT %40 MIP, IMT %50-60-70-80
- Keywords
- Respiratory Muscle Training, Functional Performance, Strength, MaxVO₂, Athlete
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
IMT %40 MIPDevice
Also called The Constant IMT group trained with a fixed resistance of 40% MIP throughout the intervention.
This study examined two inspiratory muscle training (IMT) protocols using the PowerBreathe device. Participants in both groups performed IMT twice daily, five days a week, for four weeks. Each session included 30 inspiratory breaths, totaling 60 breaths per day.
The Constant IMT group trained with a fixed resistance of 40% MIP throughout the intervention.
All participants received supervised instruction during the initial session. Subsequent sessions were home-based, monitored weekly through video submissions and participant check-ins. This design enables a structured comparison between progressive and constant loading in IMT for improving respiratory strength and endurance in trained athletes.
IMT %50-60-70-80Device
Also called The Incremental IMT group began training at 50% of Maximal Inspiratory Pressure (MIP), with resistance increased weekly to 60%, 70%, and 80%.
This study examined two inspiratory muscle training (IMT) protocols using the PowerBreathe device. Participants in both groups performed IMT twice daily, five days a week, for four weeks. Each session included 30 inspiratory breaths, totaling 60 breaths per day.
The Incremental IMT group began training at 50% of Maximal Inspiratory Pressure (MIP), with resistance increased weekly to 60%, 70%, and 80%.
All participants received supervised instruction during the initial session. Subsequent sessions were home-based, monitored weekly through video submissions and participant check-ins. This design enables a structured comparison between progressive and constant loading in IMT for improving respiratory strength and endurance in trained athletes.
| Study group | Role | What they receive |
|---|---|---|
| Constant IMT Group | Experimental | Athletes performed fixed-resistance inspiratory muscle training using a PowerBreathe threshold device twice daily, 5 days per week for 4 weeks (2 sets of 30 repetitions/day) maintained at a constant 40% MIP throughout the intervention. Receives: Device: IMT %40 MIP |
| Incremental IMT Group | Experimental | Athletes performed progressive inspiratory muscle training using a PowerBreathe threshold device twice daily, 5 days per week for 4 weeks (2 sets of 30 repetitions/day). Resistance started at 50% MIP and increased weekly by 10% (50%, 60%, 70%, and 80% MIP). Receives: Device: IMT %50-60-70-80 |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in maximal inspiratory pressure (MIP)
Maximal inspiratory pressure (MIP) will be measured using a device with a respiratory pressure measurement function and expressed in cmH2O. Change will be calculated as the Week 4 value minus the baseline value.
Measured: Baseline and Week 4 (end of the intervention).
Change in Maximal Expiratory Pressure (MEP)
Maximal expiratory pressure was measured from total lung capacity against an occluded airway using a digital respiratory pressure meter (MicroRPM) and expressed in cmH2O. Change was calculated as Week 4 minus baseline.
Measured: Baseline and Week 4 (end of the intervention).
Secondary outcomes (16)
Change in forced vital capacity (FVC)
Forced vital capacity (FVC) will be measured by spirometry and expressed in liters. Change will be calculated as the Week 4 value minus the baseline value.
Measured: Baseline and Week 4 (end of the intervention).
Change in Forced Expiratory Volume in 1 Second (FEV1)
Volume exhaled in the first second of a forced exhalation maneuver was measured using spirometry, expressed in liters (L).
Measured: Baseline and Week 4 (end of the intervention).
Change in FEV1/FVC Ratio
The ratio of forced expiratory volume in 1 second to forced vital capacity was assessed using spirometry, expressed as a percentage (%).
Measured: Baseline and Week 4 (end of the intervention).
Change in Slow Vital Capacity (SVC)
Vital capacity measured during relaxed, unforced breathing using spirometry, expressed in liters (L).
Measured: Baseline and Week 4 (end of the intervention).
Change in Maximal Voluntary Ventilation (MVV)
Maximal volume of air ventilated over a 12-second sprint breathing protocol was extrapolated to liters per minute (L/min).
Measured: Baseline and Week 4 (end of the intervention).
Change in Seated Medicine Ball Throw Distance
Upper body explosive power was measured by throwing a 3 kg medicine ball overhead from a seated position with the back supported against a wall. The maximum distance achieved across three trials was recorded in centimeters (cm).
Measured: Baseline and Week 4 (end of the intervention).
Change in 30-Second Modified Push-Up Repetitions
Upper body muscular endurance was evaluated by counting the maximum number of correctly executed push-up repetitions performed within 30 seconds.
Measured: Baseline and Week 4 (end of the intervention).
Change in 1-Minute Sit-Up Repetitions
Abdominal muscular endurance was evaluated by recording the maximum number of correctly executed sit-up repetitions completed in 60 seconds.
Measured: Baseline and Week 4 (end of the intervention).
Change in 1-Repetition Maximum (1RM) Bench Press Strength
Maximal upper body dynamic strength was assessed via 1RM barbell bench press test protocol, expressed in kilograms (kg).
Measured: Baseline and Week 4 (end of the intervention).
Change in 1-Repetition Maximum (1RM) Back Squat Strength
Maximal lower body dynamic strength was determined using a standard 1RM barbell back squat protocol, expressed in kilograms (kg).
Measured: Baseline and Week 4 (end of the intervention).
Change in Isometric Hand Grip Strength
Isometric hand grip strength was assessed using a Takei hand dynamometer for dominant and non-dominant hands, recorded in kilograms (kg).
Measured: Baseline and Week 4 (end of the intervention).
Change in Isometric Back and Leg Strength
Isometric back and leg strength were evaluated using a Takei digital back-and-leg dynamometer, recorded in kilograms (kg).
Measured: Baseline and Week 4 (end of the intervention).
Change in Vertical Jump Height
Explosive lower extremity power was evaluated via vertical jump test using a jump meter (KK 5406 Jumpmeter). The best attempt was recorded in centimeters (cm).
Measured: Baseline and Week 4 (end of the intervention).
Change in Single Leg Hop Performance and Limb Symmetry Index
Functional lower extremity performance was measured using single-leg hop test protocols (single hop, triple hop, crossover hop, and side hop). Maximum distance was recorded in cm, and the Limb Symmetry Index (LSI, %) was calculated.
Measured: Baseline and Week 4 (end of the intervention).
Change in Anaerobic Peak and Mean Power (Wingate Test)
Anaerobic power was evaluated using a 30-second all-out Wingate test on a Monark 894E cycle ergometer against a resistance of 7.5% body weight, expressed in Watts (W).
Measured: Baseline and Week 4 (end of the intervention).
Change in Estimated Maximal Oxygen Consumption (VO2max)
Aerobic capacity was evaluated using the Bruce Treadmill Test protocol. The test began on a motorized treadmill at 2.74 km/h and a 10% incline, with speed and incline increasing every 3 minutes until volitional exhaustion. Total test duration (T, in minutes) was recorded, and VO2max was estimated using the standardized regression equation: VO2max = 14.8 - (1.379 * T) + (0.451 * T^2) - (0.012 * T^3), expressed in mL/kg/min. Change was calculated as Week 4 minus baseline.
Measured: Baseline and Week 4 (end of the intervention) .
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Oct 2026
- Study start15 Sep 2024
- Primary completion10 Nov 2024
- Study completion11 Nov 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (8)Papers the sponsor has linked to this study.
- Other trials for Respiratory Muscle TrainingStudies 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
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- A randomized, controlled, double-blind, parallel-group clinical trial comparing constant versus incremental threshold inspiratory muscle training in trained athletes.
- Masking
- Double blind
- Who is masked
- Participant, Outcomes assessor
- Enrolment
- 23 participants (actual)
Sponsor and investigators
- Lead sponsor
- Ondokuz Mayıs University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Ali Kerim Yılmaz, Ondokuz Mayıs University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07887282
- Sponsor's protocol ID
- RMT-Athlete-2025
- Status last verified
- Oct 2026
- First submitted
- 2 Jan 2026
- Last updated
- 21 Oct 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Gomes Neto M, Ferrari F, Helal L, Lopes AA, Carvalho VO, Stein R. The impact of high-intensity inspiratory muscle training on exercise capacity and inspiratory muscle strength in heart failure with reduced ejection fraction: a systematic review and meta-analysis. Clin Rehabil. 2018 Nov;32(11):1482-1492. doi: 10.1177/0269215518784345. Epub 2018 Jul 9.
PubMed 29984598Gething AD, Williams M, Davies B. Inspiratory resistive loading improves cycling capacity: a placebo controlled trial. Br J Sports Med. 2004 Dec;38(6):730-6. doi: 10.1136/bjsm.2003.007518.
PubMed 15562168Fernandez-Lazaro D, Gallego-Gallego D, Corchete LA, Fernandez Zoppino D, Gonzalez-Bernal JJ, Garcia Gomez B, Mielgo-Ayuso J. Inspiratory Muscle Training Program Using the PowerBreath(R): Does It Have Ergogenic Potential for Respiratory and/or Athletic Performance? A Systematic Review with Meta-Analysis. Int J Environ Res Public Health. 2021 Jun 22;18(13):6703. doi: 10.3390/ijerph18136703.
PubMed 34206354Cunha M, Mendes F, Paciencia I, Rodolfo A, Carneiro-Leao L, Rama T, Rufo J, Delgado L, Moreira A. The effect of inspiratory muscle training on swimming performance, inspiratory muscle strength, lung function, and perceived breathlessness in elite swimmers: a randomized controlled trial. Porto Biomed J. 2019 Oct 24;4(6):e49. doi: 10.1097/j.pbj.0000000000000049. eCollection 2019 Nov-Dec.
PubMed 33501396Charususin N, Dacha S, Gosselink R, Decramer M, Von Leupoldt A, Reijnders T, Louvaris Z, Langer D. Respiratory muscle function and exercise limitation in patients with chronic obstructive pulmonary disease: a review. Expert Rev Respir Med. 2018 Jan;12(1):67-79. doi: 10.1080/17476348.2018.1398084. Epub 2017 Nov 6.
PubMed 29072087Chang YC, Chang HY, Ho CC, Lee PF, Chou YC, Tsai MW, Chou LW. Effects of 4-Week Inspiratory Muscle Training on Sport Performance in College 800-Meter Track Runners. Medicina (Kaunas). 2021 Jan 15;57(1):72. doi: 10.3390/medicina57010072.
PubMed 33467421Piskin NE, Aktug ZB, Kara M, Yavuz G, Ozturk GT, Ibis S, Aka H. The Effect of Blood Flow Restriction Training on Isokinetic Strength Muscle Thickness and Athletic Performance. J Musculoskelet Neuronal Interact. 2025 Jun 1;25(2):208-218. doi: 10.22540/JMNI-25-208.
PubMed 40452197Bostanci O, Mayda H, Yilmaz C, Kabadayi M, Yilmaz AK, Ozdal M. Inspiratory muscle training improves pulmonary functions and respiratory muscle strength in healthy male smokers. Respir Physiol Neurobiol. 2019 Jun;264:28-32. doi: 10.1016/j.resp.2019.04.001. Epub 2019 Apr 3.
PubMed 30953791