This study will examine whether rigid taping applied to the acromioclavicular (AC) joint can reduce shoulder pain and improve shoulder function in people with AC joint degeneration. Participants with shoulder pain and a confirmed diagnosis of AC joint degeneration will be randomly assigned to one of two groups: (1) rigid taping plus a standardized exercise program or (2) the same exercise program without taping. The program will last 4 weeks, with weekly supervised visits. Pain, shoulder motion, and shoulder function will be assessed at baseline, after the first session (acute effect), at the end of treatment (Week 4), and at a 3-month follow-up.

Shoulder pain is one of the most common musculoskeletal complaints and can affect daily activities, work, and sports participation. Among the potential sources of shoulder pain, the acromioclavicular (AC) joint is a distinct pain generator that can often be identified through a targeted clinical examination. Diagnosis is typically based on a detailed history combined with physical tests designed to provoke AC joint symptoms, such as scarf maneuvers and localized palpation.

The AC joint is a synovial articulation between the distal clavicle and the acromion of the scapula. Although its motion is relatively limited, it plays an important role in load transfer across the shoulder girdle, particularly during arm elevation and overhead activities. AC joint symptoms may arise through different mechanisms, including degenerative changes over time, traumatic events, or inflammatory processes. Degenerative AC joint disease may coexist with other shoulder conditions, and structural changes around the joint can contribute to pain by increasing mechanical stress and altering the subacromial environment. As a result, individuals may experience pain with overhead movements, cross-body motions, lifting, pushing, or during sport-specific tasks.

Management of AC joint degeneration typically begins with conservative care. Common non-surgical strategies include physiotherapy, activity modification, temporary unloading or immobilization when needed, and symptom-directed medical management. Rehabilitation approaches generally focus on optimizing posture, improving scapular control, enhancing periscapular strength and endurance, restoring flexibility of the posterior shoulder structures, and progressively reintroducing functional loading while minimizing symptom provocation.

Taping techniques are frequently used in shoulder rehabilitation as an adjunct to exercise-based care. In clinical practice, rigid and elastic taping methods are applied with the intention of modifying joint alignment and mechanical loading, limiting painful movement patterns, and supporting more efficient scapulothoracic and glenohumeral mechanics during activity. Rigid taping, in particular, is often considered when a more structured mechanical effect is desired. While taping has been investigated in various shoulder pain presentations, existing evidence has largely focused on subacromial pain conditions and scapular kinematics rather than AC joint degeneration specifically. Consequently, there remains uncertainty about whether rigid taping provides additional clinical benefit for individuals whose primary pain source is degenerative change at the AC joint.

Therefore, the purpose of this study is to evaluate the effects of rigid AC joint taping on shoulder pain, pain-free shoulder range of motion, and shoulder function in individuals with shoulder pain associated with AC joint degeneration.

Inclusion Criteria:

• A clinical diagnosis of acromioclavicular (AC) joint degeneration confirmed by clinical examination and imaging (X-ray, ultrasound, or MRI).
• Shoulder pain duration of at least 4 weeks.
• Age between 18 and 65 years
• Willingness to refrain from any additional treatments outside the study protocol during the study period (e.g., medication changes, injections, or physiotherapy elsewhere) and to provide written informed consent

Exclusion Criteria:

• Current or previous diagnosis/history of acromioclavicular (AC) joint separation.
• Diagnosis of frozen shoulder (adhesive capsulitis).
• History of acute trauma or fracture involving the shoulder girdle (e.g., clavicle fracture, shoulder dislocation).
• History of shoulder surgery.
• Systemic inflammatory joint disease (e.g., rheumatoid arthritis) or other systemic arthropathies.
• Skin conditions preventing taping (e.g., rash, open wound, or known tape allergy).
• Neuromuscular disease or neurological disorders affecting shoulder function

Individual participant data will not be shared because specific data-sharing agreements and governance procedures have not been established.