An interventional study of Breathing-Resistance Exercise Mask and No-Mask Exercise in Respiratory Muscle Function and Football Performance, sponsored by Karabuk University. Not yet recruiting. Open to participants aged 18 Years to 30 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-30.
Sponsored by Karabuk University · Not applicable, Interventional, and Basic science
This randomized crossover study will examine the immediate effects of breathing resistance during exercise in 35 active football players aged 18-30 years. Each participant will perform the same football-related field tests under two conditions: wearing an exercise mask that adds mechanical resistance to breathing, and without the mask. The order will be randomized, with at least 72 hours between sessions. Respiratory muscle strength will be assessed before and after exercise using maximal inspiratory and expiratory mouth pressures. Heart rate, oxygen saturation, perceived exertion, breathlessness, repeated-sprint performance, and change-of-direction performance will be compared between conditions. The mask is considered a breathing-resistance device, not a method of producing genuine altitude exposure or hypoxia.
Prospective randomized-sequence, two-condition crossover study involving 35 active football players aged 18-30 years with regular football training over the preceding six months. The target allows for loss or incomplete data, with at least 32 completers sought based on a paired comparison with two-sided alpha 0.05, power 0.90, and standardized effect size 0.60.
Participants will provide written informed consent. Age, height, weight, dominant side, football experience, weekly training duration, and playing position will be recorded. Standardized preparation and familiarization will precede testing. Each participant completes a respiratory-resistance exercise-mask condition and a no-mask control condition. Condition order is computer randomized, with at least 72 hours between sessions. Participants will avoid strenuous exercise before test days and maintain comparable sleep and nutritional routines. All field testing will use the same surface, comparable environmental conditions, and standardized warm-up.
Maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) will be measured before and after exercise using a calibrated mouth-pressure device and repeated acceptable and reproducible maneuvers. These are noninvasive measures of respiratory muscle function.
Heart rate and peripheral oxygen saturation (SpO2) will be monitored at standardized time points. Motion artifact, peripheral perfusion, sensor placement, and signal quality will be considered when recording pulse oximetry. Perceived exertion and breathlessness will be rated separately with the Borg category-ratio scale.
Repeated-sprint testing consists of five 30-meter linear sprints with 30-second active recovery intervals. Electronic timing records each sprint, with best, total/mean time, and performance decrement derived. The 505 change-of-direction test involves crossing the timing line, running 5 meters to a turning line, making a 180-degree turn, and returning through the timing line. Right and left turns will be standardized and electronically timed.
Testing will stop for chest pain, marked dizziness, presyncope, unusual breathlessness, or any finding judged unsafe by the researcher. No blood collection, invasive procedure, or therapeutic intervention is planned. Assessments will be conducted by the research team in an appropriate sports-field/laboratory setting.
Paired analyses will compare conditions. Repeated-measures analyses or linear mixed models will assess condition, time, and condition-by-time effects for pre/post variables including MIP and MEP. Heart rate, SpO2, perceived exertion, breathlessness, repeated-sprint performance and decrement, and 505 performance will be compared between conditions. Relationships between acute respiratory pressure changes and performance will be explored with Pearson or Spearman correlations. Sequence and period effects will be included where appropriate, and effect sizes and 95% confidence intervals will accompany inferential results. Two-sided p\<0.05 will be used.
The mask condition uses the Elevation Training Mask 2.0 (Training Mask, Inc., USA), with the original manufacturer-labeled 9,000 ft valve configuration throughout field testing. This label identifies airflow resistance, not actual altitude or verified hypoxia. The same configuration is used across participants, with fit adjusted individually. The selected setting is based on published acute crossover research (Ozdemir et al., 2026; doi:10.1186/s13102-026-01892-6). Total repeated-sprint time is the primary outcome.
Karabuk University is the lead sponsor of 142 studies on the registry; 39 are open to participants now.
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Exclusion Criteria:
Stopping and Analysis Criteria:
Participants complete standardized football field tests wearing the Elevation Training Mask 2.0 at the manufacturer-labeled 9,000 ft airflow-resistance setting, then repeat the tests without a mask at least 72 hours later. The setting denotes mechanical resistance, not actual altitude or hypoxia.
Device: Breathing-Resistance Exercise Mask · Other: No-Mask Exercise
Participants complete standardized football field tests without a mask, then repeat the tests wearing the Elevation Training Mask 2.0 at the manufacturer-labeled 9,000 ft airflow-resistance setting at least 72 hours later.
Device: Breathing-Resistance Exercise Mask · Other: No-Mask Exercise
Elevation Training Mask 2.0 (Training Mask, Inc., USA), using the original manufacturer-labeled 9,000 ft resistance configuration during standardized repeated-sprint and 505 change-of-direction testing. Fit is adjusted individually; the same valve configuration is used for all participants. The label represents mechanical airflow resistance and does not establish hypoxia or altitude equivalence.
The same standardized warm-up, five 30-meter sprints with 30-second active recovery, and 505 change-of-direction testing are performed without a breathing-resistance mask. Sessions are separated by at least 72 hours and use comparable testing conditions.
Total Repeated-Sprint Time
Sum of electronically timed completion times, in seconds, for five 30-meter linear sprints separated by 30-second active recovery. Lower values indicate better performance. Mask and no-mask conditions are compared within participants.
Time frame: During repeated-sprint testing in each of two sessions separated by at least 72 hours.
Best and Mean Sprint Time
Best (minimum) and arithmetic mean electronically timed 30-meter sprint completion times, reported separately in seconds across five sprints. Lower values indicate better performance.
Time frame: During repeated-sprint testing in each session; sessions at least 72 hours apart.
Repeated-Sprint Performance Decrement
Percentage decrement calculated as 100 x \[(total sprint time / (best sprint time x 5)) - 1\]. Higher percentages indicate greater performance decrement.
Time frame: During repeated-sprint testing in each session; sessions at least 72 hours apart.
Maximal Inspiratory Pressure
Maximal inspiratory mouth pressure (MIP), in cmH2O, obtained with a calibrated pressure device using acceptable, reproducible maneuvers. Pre-to-post exercise changes are compared between conditions.
Time frame: Before and immediately after exercise in each of two sessions at least 72 hours apart.
Maximal Expiratory Pressure
Maximal expiratory mouth pressure (MEP), in cmH2O, obtained with a calibrated pressure device using acceptable, reproducible maneuvers. Pre-to-post exercise changes are compared between conditions.
Time frame: Before and immediately after exercise in each of two sessions at least 72 hours apart.
505 Change-of-Direction Time
Electronically timed 505 test completion time, in seconds, with right and left turning directions recorded separately. Lower values indicate better performance.
Time frame: During 505 testing in each session; sessions at least 72 hours apart.
Heart Rate
Heart rate in beats per minute recorded before exercise, during testing where signal quality permits, and immediately after exercise. Corresponding assessment points are compared between conditions.
Time frame: Before, during and immediately after exercise in each session; sessions at least 72 hours apart.
Peripheral Oxygen Saturation
Peripheral oxygen saturation (SpO2), expressed as a percentage, measured by pulse oximetry. Valid signals at corresponding assessment points are compared between conditions.
Time frame: Before, during and immediately after exercise in each session; sessions at least 72 hours apart.
Perceived Exertion and Breathlessness
Perceived exertion and breathlessness are rated separately using the Borg category-ratio 0-10 scale; higher scores indicate greater exertion or breathlessness.
Time frame: Immediately after each field test in each session; sessions at least 72 hours apart.
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Plan to share: Undecided
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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