Diaphragmatic Facilitation and Upper Extremity Performance in Volleyball Players

NCT07784517 | Recruiting

• 1 other identifier: 2025/07
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 1

Brief Summary

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.

Conditions

Volleyball Players

Keywords

Diaphragm; Diaphragmatic Facilitation; Volleyball Players; Upper Extremity Performance; Respiratory Function; Respiratory Muscle Strength; Manual Therapy; Sports Physiotherapy

Outcome Measures

Primary Outcomes (8)

• Forced Vital Capacity

  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

  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

  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

  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

  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

  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

  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

  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

Study Arms (2)

Intervention Group

EXPERIMENTAL

Diaphragmatic Facilitation Group

Other: Diaphragmatic Facilitation

Control Group

EXPERIMENTAL

Sham Control Group

Other: Sham Facilitation

Interventions

Diaphragmatic Facilitation OTHER

Following a standardized dynamic warm-up, participants in the intervention group will receive a single session of manual resisted diaphragmatic facilitation.

Intervention Group

Sham Facilitation OTHER

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.

Control Group

Eligibility Criteria

• Age: 18 Years - 30 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Istinye University: lead

Study Sites (1)

Istinye University

Istanbul, 34010, Turkey (Türkiye)

RECRUITING

MeSH Terms

Conditions

Respiratory Aspiration

Condition Hierarchy (Ancestors)

Respiration Disorders; Respiratory Tract Diseases; Pathologic Processes; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, OUTCOMES ASSESSOR
• Masking Details: Participants and outcome assessors will be blinded to group allocation. Participants will not be informed whether they receive manual resisted diaphragmatic facilitation or the sham intervention. Outcome assessments will be performed by an assessor who is unaware of the participants' group assignments. The physiotherapist administering the interventions cannot be blinded due to the nature of the procedures.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Asst. Prof.

Model Details: This study is designed as a two-arm, randomized, sham-controlled trial using stratified randomization. Thirty volleyball players who provide informed consent will be allocated to either the Diaphragmatic Facilitation Group or the Sham Control Group.

Study Record Dates

• First Submitted: August 21, 2026
• First Posted: August 25, 2026
• Study Start: August 30, 2026
• Primary Completion (Estimated): November 15, 2026
• Study Completion (Estimated): November 30, 2026
• Last Updated: October 1, 2026

Record last verified: 2026-09

Locations

TU (1)