Inspiratory Muscle Warm-Up in Combat Athletes

Primary outcomes

1. Kickboxing Fitness Test performance

   Time frame: Across 3 study days, measured immediately after each intervention session.

   The Kickboxing Fitness Test is a valid and reliable field-based assessment designed to evaluate sport-specific technical skills and anaerobic performance in kickboxers.The test consists of 3 rounds of 2 minutes each, separated by 1 minute of passive recovery. In each round, athletes complete four 30-second technical sections involving punch and kick combinations, with 10 m running between stations, while aiming to perform each technique with maximal speed and accuracy.

2. Forced Vital Capacity (FVC)

   Time frame: Across 3 study days, at baseline, immediately after the 15-minute standard warm-up, immediately before and after the intervention, during each 1-minute rest interval of the Kickboxing Fitness Test (every 2 minutes), and immediately after the test

   This is the maximum total volume of air that can be forcibly exhaled after taking the deepest possible breath in.

3. Forced Expiratory Volume in 1 Second (FEV1)

   Time frame: Across 3 study days, at baseline, immediately after the 15-minute standard warm-up, immediately before and after the intervention, during each 1-minute rest interval of the Kickboxing Fitness Test (every 2 minutes), and immediately after the test

   This is the volume of air that can be forcibly exhaled from the lungs in the first second of a pulmonary function test.

4. Ratio of Forced Expiratory Volume in 1 Second to Forced Vital Capacity (FEV1/FVC)

   Time frame: Across 3 study days, at baseline, immediately after the 15-minute standard warm-up, immediately before and after the intervention, during each 1-minute rest interval of the Kickboxing Fitness Test (every 2 minutes), and immediately after the test

   This is the ratio of forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC), used to assess airflow limitation during pulmonary function testing.

5. Peak Expiratory Flow (PEF)

   Time frame: Across 3 study days, at baseline, immediately after the 15-minute standard warm-up, immediately before and after the intervention, during each 1-minute rest interval of the Kickboxing Fitness Test (every 2 minutes), and immediately after the test

   This is the highest flow rate achieved during a forceful expiration after taking the deepest possible breath in, used to reflect expiratory flow capacity.

6. Maximal Inspiratory Pressure (MIP)

   Time frame: Across 3 study days, at baseline, immediately after the 15-minute standard warm-up, immediately before and after the intervention, during each 1-minute rest interval of the Kickboxing Fitness Test (every 2 minutes), and immediately after the test

   This is the maximum pressure generated during a forceful inspiration against a closed airway, used to assess inspiratory muscle strength.

7. Maximal Expiratory Pressure (MEP)

   Time frame: Across 3 study days, at baseline, immediately after the 15-minute standard warm-up, immediately before and after the intervention, during each 1-minute rest interval of the Kickboxing Fitness Test (every 2 minutes), and immediately after the test

   This is the maximum pressure generated during a forceful expiration against a closed airway, used to assess expiratory muscle strength.

8. Heart Rate (HR)

   Time frame: Across 3 study days, throughout the entire test session

   This is the number of heart beats per minute, used to assess the cardiovascular response to exercise and recovery.

9. Rating of perceived exertion (RPE)

   Time frame: Across 3 study days, at baseline, immediately after the 15-minute standard warm-up, immediately before and after the intervention, during each 1-minute rest interval of the Kickboxing Fitness Test (every 2 minutes), and immediately after the test

   Rating of perceived exertion (RPE) will be measured to evaluate the participants' subjective perceptual responses. These measurements are used to assess the overall perception of physical strain in response to exercise. The level of perceived exertion will be assessed using the Category Ratio-10 (CR-10) scale, which was developed and modified by Foster et al. (2001) and includes ratings ranging from 0 to 10. This scale allows participants to rate the overall difficulty they experience during exercise from 0 (nothing at all) to 10 (maximal difficulty).

10. Perceived Dyspnea

    Time frame: Across 3 study days, at baseline, immediately after the 15-minute standard warm-up, immediately before and after the intervention, during each 1-minute rest interval of the Kickboxing Fitness Test (every 2 minutes), and immediately after the test

    Perceived dyspnea will be assessed using the Category Ratio-10 (CR-10) scale, which enables participants to report their level of respiratory discomfort or breathing difficulty. Scores range from 0 to 10, with higher scores indicating greater breathing difficulty.