Acute Effects of Inspiratory Muscle Warm-up on Muscular Performance and Pulmonary Function in Natural Bodybuilders (IWU and 1RM)

May 1, 2026 updated by: Coşkun YILMAZ, Gümüşhane Universıty

The present study aims to investigate the acute effects of inspiratory muscle warm-up (IWU) on 1RM performance in professional natural bodybuilders. The hypothesis is that IWU will lead to an increase in the pressure-generating capacity of the inspiratory muscles, thereby resulting in improved 1RM strength performance. The anticipated findings are expected to contribute not only to the enhancement of maximal strength performance but also to the improvement of exercise efficiency through increased respiratory muscle endurance. It is submitted that these outcomes may ultimately provide insights into the long-term sustainability of professional athletes' performance.

Twenty male athletes who had competed in national and international professional natural bodybuilding competitions were recruited for this study. The participants had an average experience in natural bodybuilding of 3.21 years, with a standard deviation of ± 1.44 years, and trained for more than five hours per week. The data collection period commenced in July 2025. The study was designed as a randomized controlled experimental trial. Participants were randomly assigned to two groups by a computerized program at three visits after the trial, based on their first measurement: inspiratory warm-up (IWU) group or control (CON) group.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

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

The data collection period occurred between the 1st and 6th of July 2025. Prior to their involvement in the study, all subjects provided both verbal and written informed consent. Participants were invited to visit the laboratory on three separate occasions. During the preliminary visit, the subjects underwent a series of pulmonary function tests (PFTs). These included measurements of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP). The participants were also subjected to 1RM testing and three practice trials of both the inspiratory warm-up and general training warm-up procedures [14]. On the second occasion, the PFT and MIP-MEP tests were conducted without any warm-up protocols, followed by the assessment of 1RM performance. On the third occasion, the participants were divided into two groups: the experimental group (IWU), which performed both inspiratory muscle and general warm-up exercises, and the control group (CON), which performed only the general warm-up. Each group comprised ten professional male natural bodybuilders. PFT and MIP-MEP tests were reassessed, and 1RM performance was measured immediately following the IWU intervention. In order to control for circadian variations, all laboratory visits were conducted at the same time of day (between 09:00 and 12:00). Participants were notified 72 hours in advance of each visit and were instructed to refrain from high-intensity physical activity during that period. It was determined that a recovery period of 72 hours should be observed between each testing session.

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.
Interventional

Enrollment (Actual)

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.
27

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Turkey (Türkiye)
    • Gümüşhane Province
      • Gümüşhane, Gümüşhane Province, Turkey (Türkiye), (542) 442-7444
        • Gumushane Univetsity

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

Description

Inclusion Criteria:

  • They were professional natural bodybuilders with less than three years of experience. ,

  • Male professional natural bodybuilders aged 18-35 years

    --Full participation in training and matches during the previous 6 months,

  • Ability to perform maximal exercise testing

Exclusion Criteria:

  • Individuals were deemed ineligible on the basis of a medical history that included any chronic or acute respiratory disease.
  • Individuals were considered ineligible if they were taking any prescription medication that could affect their response to exercise.
  • In accordance with the stipulated criteria, individuals were deemed to be ineligible for participation in the study if they had a history of current smoking or had smoked within the past year.
  • Individuals were considered ineligible for participation in the study if they had participated in similar studies within the previous six months.
  • Prior to participation, all individuals were required to sign a formal waiver, thereby affirming their adherence to the World Anti-Doping Agency Code.

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

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
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.
Other: IWU
The IWU group performed both inspiratory muscle warm-up and standard exercise warm-up.
Other: IWU
The IWU group performed both inspiratory muscle warm-up and standard exercise warm-up.
Other Names:
  • Inspiratory muscle warm-up
Other: Control
The CON group performed only the standard warm-up.
Other: Control Group
The CON group performed only the standard warm-up.
Other: IWU
The IWU group performed both inspiratory muscle warm-up and standard exercise warm-up.
Other Names:
  • Inspiratory muscle warm-up
Other: Control
The CON group performed only the standard warm-up.

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
1RM
Time Frame: Day 1
One-Repetition maximum (1RM) bench press performance
Day 1
maximal inspiratory pressures (MIP )
Time Frame: Day 1
maximal inspiratory pressures (MIP )
Day 1

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
maximal expiratory pressures (MEP)
Time Frame: Day 1
maximal expiratory pressures (MEP)
Day 1
Forced vital capacity (FVC)
Time Frame: Day 1
Pulmonary function parameter, including forced vital capacity (FVC), the total volume of air exhaled forcefully after a maximal deep inhalation, were measured using a MGF Diagnostics CPFS/D USB spirometer
Day 1
forced expiratory volume in one second (FEV1)
Time Frame: Day 1
Pulmonary function parameter, including forced vital capacity (FEV1), the total volume of air exhaled forcefully after a maximal deep inhalation, were measured using a MGF Diagnostics CPFS/D USB spirometer
Day 1
FEV1/FVC ratio (Tiffeneau index)
Time Frame: Day 1
Pulmonary function parameter, including forced vital capacity (FEV1/FVC), the total volume of air exhaled forcefully after a maximal deep inhalation, were measured using a MGF Diagnostics CPFS/D USB spirometer
Day 1
peak expiratory flow (PEF)
Time Frame: Day 1
Pulmonary function parameter, including forced vital capacity (FVC), the total volume of air exhaled forcefully after a maximal deep inhalation, were measured using a MGF Diagnostics CPFS/D USB spirometer
Day 1

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.
Gümüşhane Universıty

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Çankırı Karatekin University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Coşkun YILMAZ, associate professor, Gumushane 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 (Actual)

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.
January 5, 2025

Primary Completion (Actual)

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.
April 15, 2025

Study Completion (Actual)

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.
January 5, 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).
January 18, 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.
January 28, 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.
February 5, 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.
May 7, 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 1, 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

Keywords

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.
  • 2025/0014

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data (IPD) will not be shared because the dataset consists of a small sample of elite athletes, and sharing de-identified data could still pose a risk of participant re-identification. In addition, no data-sharing agreement or participant consent for IPD sharing was established at the time of study design. Aggregate data supporting the findings are reported within the published article.

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.

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