Respiratory Function and Athletic Performance in Professional Soccer Players

May 23, 2026 updated by: Yunus Emre Tutuneken, Istinye University

Association Between Respiratory Function and Athletic Performance Parameters in Professional Soccer Players: A Cross-Sectional Study

This prospective observational study aims to investigate the relationship between respiratory function and multidimensional athletic performance parameters in professional soccer players. The primary hypothesis of the study is that soccer players with enhanced respiratory function and superior respiratory muscle strength will exhibit optimized motor performance outcomes and shorter (faster) reactive reaction times. Investigators will evaluate respiratory muscle strength, spirometric pulmonary functions, dynamic balance, core and abdominal endurance, and reactive visuomotor reaction times during a single testing session within the competitive season.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Professional soccer players from Istanbulspor A.S. Football Club will be screened and enrolled based on strict eligibility criteria. Eligible athletes will undergo a comprehensive, single-session testing protocol designed to prevent fatigue-related bias. Testing will commence with a baseline pulmonary function assessment and respiratory muscle strength evaluation (maximal inspiratory pressure [MIP] and maximal expiratory pressure [MEP]). Following a standardized rest interval, dynamic balance will be quantified using the Y-Balance Test (YBT). Subsequently, reactive visuomotor reaction times will be measured using the wireless BlazePod LED system. Finally, participants will execute higher-intensity, sport-specific performance assessments, including the isometric plank test for core endurance, a 60-second timed sit-up test for abdominal muscular endurance, and the T-drill test for agility. A standardized 10-minute seated rest interval will be strictly enforced between all physical assessments to ensure full physiological recovery. Bivariate correlation models will be utilized to analyze the direct relationships between respiratory indicators and performance indices.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Observational

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
31

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Sampling Method

Non-Probability Sample

Study Population

The study population will consist of elite-level athletic professionals, specifically young adult male professional soccer players. Participants will be recruited from a licensed professional football club actively competing in national league training and competition schedules.

Description

Inclusion Criteria:

  • Participants will be actively competing, licensed professional soccer players. -Participants will be engaged in regular, team-based training and competitive match schedules.
  • Participants will voluntarily provide written informed consent before any study-related physical performance assessments are conducted.

Exclusion Criteria:

  • Participants will be excluded if they present with an acute upper or lower respiratory tract infection that could potentially affect pulmonary function or maximal respiratory muscle performance.
  • Participants will be excluded if they have a documented history of major cardiothoracic surgery.
  • Participants will be excluded if they have any diagnosed respiratory and/or cardiovascular disorder associated with dyspnea or impaired pulmonary mechanics.
  • Participants will be excluded if they present with any condition that elevates clinical risk during maximal inspiratory and expiratory pressure assessments.
  • Participants will be excluded if they have sustained an acute musculoskeletal injury within the preceding 6 weeks that could compromise maximal physical exertion during sport-specific performance testing.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Maximal Expiratory Pressure (MEP)
Time Frame: 2 hours
Description: Respiratory muscle strength will be assessed using a portable digital respiratory pressure meter. Participants will execute a maximal expiratory maneuver from total lung capacity after full inspiration while wearing a nose clip. The highest reproducible value from at least three technically acceptable trials will be recorded in centimeters of water (cmH₂O).
2 hours
Maximal Inspiratory Pressure (MIP)
Time Frame: 2 hour
Description: Respiratory muscle strength will be assessed using a portable digital respiratory pressure meter. Participants will perform a maximal inspiratory maneuver from residual volume following complete expiration while wearing a nose clip. The highest reproducible value from at least three technically acceptable trials will be recorded in centimeters of water (cmH₂O).
2 hour
Reactive Visuomotor Reaction Time
Time Frame: 2 hours
Cognitive-motor reaction speed will be quantified using a wireless LED pod system arrayed in an equidistant semi-circular matrix. Participants will utilize their dominant lower limb to deactivate randomly illuminated pods as quickly as possible across 10 sets of 22 randomized stimuli. The mean reaction time across the challenge will be recorded in milliseconds (ms).
2 hours
Dynamic Postural Stability (Y-Balance Test)
Time Frame: 2 hours
Functional reach capacity and dynamic balance will be quantified using a standardized Y-Balance Test apparatus. While maintaining a single-leg stance, participants will push indicator blocks in the anterior, posteromedial, and posterolateral directions. The maximum reach distance from three successful trials for each direction will be normalized to leg length and used to calculate a comprehensive Composite Score percentage (%) for both limbs.
2 hours
Static Core Stabilization Endurance (Prone Plank Test)
Time Frame: 2 hours
Isometric core endurance will be quantified using the isometric prone plank test on a high-density mat. Participants will support their body weight exclusively on their forearms and toes, maintaining a strict neutral horizontal alignment of the head, spine, hips, and ankles. The test will be terminated when the participant voluntarily discontinues or fails to maintain correct alignment. Total duration will be recorded in seconds (sec).
2 hours

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Forced Vital Capacity (FVC)
Time Frame: 2 hours
Pulmonary function will be evaluated using a computerized spirometry system in accordance with ATS/ERS guidelines. Participants will perform a maximal inspiratory effort followed by a rapid and forceful expiration sustained until complete exhalation. The highest reproducible value will be expressed both as an absolute volume in liters (L) and as a percentage of predicted reference values (FVC%).
2 hours
Forced Expiratory Volume in 1 Second (FEV1%)
Time Frame: 2 hours
Pulmonary function will be evaluated using a computerized spirometry system in accordance with ATS/ERS guidelines. The volume of air exhaled during the first second of the FVC maneuver will be extracted. The highest reproducible value will be expressed both as an absolute volume in liters (L) and as a percentage of predicted reference values (FEV1%).
2 hours
Peak Expiratory Flow (PEF)
Time Frame: 2 hours
Pulmonary function will be evaluated using a computerized spirometry system in accordance with ATS/ERS guidelines. The maximum flow rate achieved during the forced expiratory maneuver will be measured. The highest reproducible value will be expressed in liters per second (L/s) and as a percentage of predicted reference values (PEF%).
2 hours
Dynamic Abdominal Endurance (60-Second Sit-Up Test)
Time Frame: 2 hours
Dynamic muscular endurance of the abdominal wall will be evaluated using a timed sit-up protocol. From a supine position with knees flexed at 90° and hands crossed over the chest, participants will flex the trunk until the elbows touch the knees, then return to the baseline position. The total number of correctly executed repetitions completed within exactly 1 minute (reps) will be recorded.
2 hours
Change-of-Direction Speed and Agility (T-Drill Test)
Time Frame: 2 hours
On-field agility and change-of-direction speed will be quantified using a standardized T-configuration cone course monitored by electronic timing gates. Participants will perform forward sprinting, lateral side-shuffling, and backpedaling maneuvers through the course. The fastest completion time out of three successful trials will be recorded in seconds (sec).
2 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Istinye University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 25, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
July 5, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 10, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 23, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 23, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 1, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 1, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 23, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 22

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

Cookie Settings

We use cookies to ensure that we give you the best experience on our website. For more details carefully read our Privacy and Cookies Policy. ...>>>You can change your preferences or withdraw your consent at any time by deleting the cookies from your website or computer as described in the policy. Please accept it and choose your preferences by ticking the corresponding boxes in the "Manage Settings" section below. Please carefully read our Terms of Service before you proceed with using any part of this website.
«Manage Settings