Diaphragmatic Facilitation and Upper Extremity Performance in Volleyball Players

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.

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.