This randomized controlled trial aims to investigate the effects of Mobilization With Movement (MWM) combined with exercise therapy on tendon morphology, pain, and functional outcomes in individuals with rotator cuff tendinopathy. A total of approximately 60 participants diagnosed with supraspinatus tendinopathy will be randomly assigned to either an exercise-only group or an exercise plus MWM group.

All participants will undergo a standardized rehabilitation program for 8 weeks. Clinical outcomes, including pain intensity (Visual Analog Scale), shoulder function (SPADI and QuickDASH), range of motion, muscle strength, proprioception, and psychosocial status (Tampa Scale of Kinesiophobia, Pain Catastrophizing Scale, and Central Sensitization Inventory), will be assessed at baseline and post-intervention. In addition, ultrasound imaging will be used to evaluate tendon morphology, including tendon thickness, subacromial bursa thickness, acromiohumeral distance, echogenicity, and vascularity.

The primary objective is to determine whether MWM produces superior improvements in clinical outcomes and whether it is associated with measurable changes in tendon structure as assessed by ultrasound. The findings are expected to contribute to a better understanding of the biomechanical and neurophysiological mechanisms underlying manual therapy in rotator cuff tendinopathy and to provide evidence for its role in musculoskeletal rehabilitation.

Rotator cuff tendinopathy is one of the most common causes of shoulder pain and functional limitation, often resulting in reduced quality of life and impaired upper extremity performance. Although exercise therapy is widely accepted as the cornerstone of conservative management, the additional benefit of manual therapy techniques, particularly Mobilization With Movement (MWM), remains an area of ongoing investigation. Furthermore, the potential effects of manual therapy on tendon morphology assessed via ultrasound imaging are not yet fully understood.

This randomized controlled trial will examine whether the addition of MWM to a standardized exercise program provides superior outcomes compared to exercise alone in individuals with supraspinatus tendinopathy. Participants will be randomly allocated into two groups: an exercise-only group and an exercise plus MWM group. Both interventions will be delivered over an 8-week period.

The study will focus on both clinical and imaging-based outcomes. Clinical outcomes include pain intensity, shoulder function, range of motion, muscle strength, proprioception, and psychosocial factors such as fear of movement, pain catastrophizing, and central sensitization. Imaging outcomes will be assessed using musculoskeletal ultrasound to evaluate tendon thickness, subacromial bursa thickness, acromiohumeral distance, echogenicity, and vascularity.

The primary aim is to determine whether MWM induces superior improvements in pain and function and whether these changes are accompanied by measurable alterations in tendon morphology. Secondary aims include exploring the relationship between ultrasound-based structural changes and clinical outcomes, as well as evaluating the potential role of psychosocial factors in treatment response.

This study is expected to provide new evidence regarding the structural and functional effects of manual therapy in rotator cuff tendinopathy and to clarify whether improvements in clinical symptoms are associated with objective changes in tendon morphology.

Inclusion Criteria:

• Age between 18 and 65 years
• Clinical diagnosis of rotator cuff tendinopathy (supraspinatus involvement) confirmed by musculoskeletal ultrasound
• Shoulder pain duration of at least 3 months
• Pain intensity ≥ 3/10 on the Visual Analog Scale (VAS)
• Ability to understand and follow instructions and complete questionnaires

Exclusion Criteria:

• Full-thickness or large rotator cuff tear confirmed by ultrasound or MRI
• History of shoulder surgery on the affected side
• Diagnosis of adhesive capsulitis (frozen shoulder)
• Shoulder instability or dislocation history
• Cervical radiculopathy or referred neck-related shoulder pain
• Inflammatory rheumatic diseases (e.g., rheumatoid arthritis, ankylosing spondylitis)
• Neurological disorders affecting upper extremity function
• Corticosteroid injection in the shoulder within the last 6 months
• Ongoing physiotherapy or manual therapy treatment for shoulder pain in the last 3 months
• Severe systemic or psychiatric conditions that may interfere with participation

Due to the nature of the interventions, participants and care providers cannot be blinded to group allocation. However, outcome assessments will be performed by an independent assessor who is blinded to group assignment. The assessor will not be involved in the treatment process or randomization procedures. This single-blind design is used to minimize assessment bias in both clinical and ultrasound-based outcome measures.