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Completed

NCT Number: NCT07390149

Acute Effects of Inspiratory Muscle Warm-up on Muscular Performance and Pulmonary Function in Natural Bodybuilders

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.

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Key information

Age range

18 year–35 year

Sex eligibility

Male

Study type

Interventional

Phase

Not applicable

Primary location

Gumushane Univetsity

Gümüşhane, Gümüşhane Province, (542) 442-7444, Turkey (Türkiye)

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

IWU

Other

The IWU group performed both inspiratory muscle warm-up and standard exercise warm-up.

Other names: Inspiratory muscle warm-up

Control

Other

The CON group performed only the standard warm-up.

Primary outcomes

  1. 1RM

    Time frame: Day 1

    One-Repetition maximum (1RM) bench press performance

  2. maximal inspiratory pressures (MIP )

    Time frame: Day 1

    maximal inspiratory pressures (MIP )

Secondary outcomes

  1. maximal expiratory pressures (MEP)

    Time frame: Day 1

    maximal expiratory pressures (MEP)

  2. 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

  3. 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

  4. 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

  5. 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

Sponsors and collaborators

Lead sponsor

Gümüşhane Universıty

Other

Collaborators

  • Çankırı Karatekin University

Registry information

Acronym: IWU and 1RM

Important dates

Study start
2025
Primary completion
2025
Study completion
2026
First posted
Feb 5, 2026
Registry last updated
May 7, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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