The aim of this study is to investigate the immediate effects of soft tissue mobilization on shoulder mobility, pain, scapular kinematics and muscle activation and muscle Stiffness in symptomatic overhead athletes with posterior shoulder tightness.

Inclusion Criteria:

• Amateur overhead athletes aged 18-50 years.
• Participation in overhead sports training for more than 4 hours per week.
• Playing experience of more than 3 years.
• Shoulder range of motion deficits: internal rotation range of motion (ROM) on the affected side is at least 10 degrees less than the unaffected side, and total rotational ROM (internal rotation + external rotation) is at least 5 degrees less than the unaffected side, or horizontal adduction ROM is at least 10 degrees less than the unaffected side.
• Patients with subacromial pain syndrome: diagnosis requires at least 3 out of 5 positive test results (Hawkins-Kennedy impingement test, Neer impingement test, Empty Can test, Painful Arc test, and External Rotation Resistance test).

Exclusion Criteria:

• Negative result on the kinetic medial rotation test.
• History of shoulder fracture, dislocation, or upper limb injury requiring surgery within the past 6 months.
• Inability to complete the experiment due to personal factors.
• Shoulder pain intensity greater than 7 points on the Visual Analog Scale (VAS).
• History of direct trauma to the neck or upper limb within the past month. Shoulder pain and neurological symptoms originating from the cervical spine. Contraindications to soft tissue mobilization, such as open wounds in the treatment area, skin cancer, localized infection, severe edema, vascular disorders, or acute muscle tears in the treatment area