Diaphragmatic Facilitation and Upper Extremity Performance in Volleyball Players

August 25, 2026 updated by: Kubra Kardes, Istinye University

Immediate Effects of Diaphragmatic Facilitation on Upper Extremity Performance in Volleyball Players

The diaphragm contributes to both respiration and trunk stabilization. Effective diaphragmatic function may support postural control, force transfer, and upper extremity performance during dynamic activities. However, evidence regarding the immediate effects of manual diaphragmatic facilitation on upper extremity performance in athletes remains limited.

This study aims to investigate the immediate effects of manual diaphragmatic facilitation on upper extremity performance and respiratory function in actively participating volleyball players. Participants will receive an approximately 15-minute session of manual diaphragmatic facilitation. Pulmonary function, respiratory muscle strength, and upper extremity strength, stability, and endurance will be assessed immediately before and after the intervention. Assessments will include spirometry, maximal inspiratory and expiratory pressures, the Medicine Ball Throw Test, the Closed Kinetic Chain Upper Extremity Stability Test, and the Scapular Endurance Test.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

50

Phase

  • 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

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

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Aged between 18 and 30 years.
  • Regularly participating in volleyball for at least one year.
  • Training at least twice per week or actively participating in volleyball at the league or tournament level.
  • No history of a serious upper extremity or trunk injury within the previous six months, i-including injuries affecting the shoulder, scapular region, or spine.
  • No diagnosed chronic respiratory disease, including asthma, chronic obstructive pulmonary disease, or allergic bronchitis.
  • Willing and able to provide written informed consent.

Exclusion Criteria:

  • History of surgery involving the upper extremity, spine, or trunk within the previous six months, including shoulder arthroscopy or spinal disc surgery.
  • Presence of an active musculoskeletal injury, including tendinopathy, bursitis, or ligament injury.
  • Presence of a diagnosed respiratory disease, including asthma, chronic obstructive pulmonary disease, or bronchiectasis.
  • Presence of a diagnosed postural or spinal deformity that may affect study assessments, including scoliosis, clinically significant kyphosis, or clinically significant lordosis.
  • History of a neurological or cardiovascular disease.

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: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Intervention Group
Diaphragmatic Facilitation Group
Other: Diaphragmatic Facilitation
Following a standardized dynamic warm-up, participants in the intervention group will receive a single session of manual resisted diaphragmatic facilitation.
Experimental: Control Group
Sham Control Group
Other: Sham Facilitation
Participants in the control group will complete the same dynamic warm-up protocol, followed by a sham intervention consisting of superficial, non-facilitatory palpation and general breathing instructions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Forced Vital Capacity
Time Frame: 4 weeks
Forced vital capacity is the maximum volume of air that a participant can forcibly exhale after taking the deepest possible breath. It will be measured by spirometry and recorded in liters. Higher values generally indicate greater ventilatory capacity, whereas lower values may indicate reduced pulmonary capacity or expiratory limitation.
4 weeks
Forced Expiratory Volume in One Second
Time Frame: 4 weeks
Forced expiratory volume in one second is the volume of air that a participant can forcibly exhale during the first second of a forced expiratory maneuver. It will be measured by spirometry and recorded in liters. Higher values generally indicate better expiratory airflow, whereas lower values may indicate reduced expiratory airflow.
4 weeks
Ratio of Forced Expiratory Volume in One Second to Forced Vital Capacity
Time Frame: 4 weeks
The ratio of forced expiratory volume in one second to forced vital capacity represents the proportion of the forced vital capacity exhaled during the first second of a forced expiratory maneuver. It will be calculated from spirometric measurements and reported as a percentage. Higher values generally indicate a greater proportion of air expelled during the first second, whereas lower values may indicate expiratory airflow limitation. The results will be interpreted with consideration of age- and sex-appropriate reference values.
4 weeks
Maximal Inspiratory Pressure
Time Frame: 4 weeks
Maximal inspiratory pressure will be used to assess inspiratory muscle strength, primarily reflecting the function of the diaphragm and other inspiratory muscles. The measurement will be repeated three times, and the highest valid value will be recorded in centimeters of water. A higher absolute pressure value indicates greater inspiratory muscle strength, whereas a lower absolute pressure value indicates weaker inspiratory muscle strength.
4 weeks
Maximal Expiratory Pressure
Time Frame: 4 weeks
Maximal expiratory pressure will be used to assess expiratory muscle strength, particularly the strength of the abdominal and other expiratory muscles. The measurement will be repeated three times, and the highest valid value will be recorded in centimeters of water. A higher pressure value indicates greater expiratory muscle strength, whereas a lower pressure value indicates weaker expiratory muscle strength.
4 weeks
Medicine Ball Throw Distance
Time Frame: 4 weeks
Upper extremity explosive power will be assessed using the Medicine Ball Throw Test. The participant will sit with the back supported against a wall and the legs extended and will be instructed to throw the medicine ball as far as possible. Throwing distance will be measured in meters. A longer distance indicates greater upper extremity explosive power, whereas a shorter distance indicates lower explosive power.
4 weeks
Closed Kinetic Chain Upper Extremity Stability Test Score
Time Frame: 4 weeks
Upper extremity stability, strength, power, and endurance will be assessed using the Closed Kinetic Chain Upper Extremity Stability Test. The participant will assume a push-up position with the hands placed on two markers positioned 90 centimeters apart. The participant will alternately move each hand across the body to touch the opposite marker during the specified test period. The total number of valid touches will be recorded. A higher number of touches indicates better upper extremity functional performance and stability, whereas a lower number indicates poorer performance.
4 weeks
Scapular Muscular Endurance Time
Time Frame: 4 weeks
The functional endurance of the scapular stabilizing muscles will be assessed using the Scapular Muscular Endurance Test. An appropriately sized wooden rod will be positioned between the participant's elbows while both scapulae are maintained in a neutral position. The length of time for which the participant can maintain the standardized test position will be recorded in seconds. A longer duration indicates greater scapular muscular endurance, whereas a shorter duration indicates lower scapular muscular endurance.
4 weeks

Collaborators and Investigators

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

Sponsor

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)

August 30, 2026

Primary Completion (Estimated)

November 15, 2026

Study Completion (Estimated)

November 30, 2026

Study Registration Dates

First Submitted

August 21, 2026

First Submitted That Met QC Criteria

August 21, 2026

First Posted (Actual)

August 25, 2026

Study Record Updates

Last Update Posted (Actual)

August 27, 2026

Last Update Submitted That Met QC Criteria

August 25, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2025/07

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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