Additional Effects of Kinetic Chain Training Combined With Standard Shoulder Exercises in Subacromial Pain Syndrome

Subacromial Pain Syndrome (SAPS) is one of the most prevalent causes of non-traumatic shoulder pain, accounting for approximately 44-65% of shoulder pain cases. It is characterized by pain around the acromion that is aggravated during arm elevation, overhead activities, and lying on the affected side. Although SAPS has traditionally been considered a localized shoulder disorder, current evidence suggests that efficient shoulder function depends on coordinated movement throughout the kinetic chain, including the thoracic spine, trunk, pelvis, and lower extremities. Dysfunction of these proximal segments may alter scapular biomechanics, reduce thoracic mobility, impair muscle activation patterns, and contribute to scapular dyskinesis, ultimately increasing mechanical stress within the subacromial space. Despite this evidence, conventional rehabilitation primarily focuses on local shoulder structures, such as the rotator cuff and scapular muscles, with limited emphasis on restoring kinetic chain function.This study aims to determine whether combining kinetic chain training with standard shoulder exercises produces superior clinical outcomes compared with standard shoulder rehabilitation alone in individuals with SAPS. A single-blinded, parallel-group randomized controlled superiority trial will be conducted over one year. Forty-six participants aged 35-60 years with unilateral SAPS, symptom duration of six weeks to three months, pain intensity of 4-7 on the Numeric Pain Rating Scale (NPRS), thoracic extension range of motion below 20°, and positive clinical impingement tests will be recruited from Fauji Foundation Hospital, Rawalpindi, and Foundation University School of Health Sciences. Participants will be recruited using purposive sampling and randomly allocated into either the control or experimental group using a coin toss method. The outcome assessor will remain blinded to minimize detection bias.

Both groups will receive a standardized six-week shoulder rehabilitation program consisting of patient education, activity modification, pain-free range of motion exercises, rotator cuff \strengthening, stretching of tight musculature, and scapular muscle activation. In addition to this program, the experimental group will receive a structured kinetic chain training protocol comprising progressive lower trapezius strengthening, thoracic spine central posterior-anterior and costotransverse mobilization, activation of the longissimus and multifidus muscles using bird dog exercises, and progressive gluteus maximus strengthening through bridging exercises. All interventions will be performed within a pain-free or minimally painful range and progressed according to the participant's tolerance.

Outcome measures will be assessed at baseline and after completion of the six-week intervention. Pain intensity will be evaluated using the Numeric Pain Rating Scale (NPRS), functional disability using the Shoulder Pain and Disability Index (SPADI), shoulder abduction and external rotation range of motion using a universal goniometer, scapular upward rotation and thoracic extension using a bubble inclinometer, and shoulder and gluteus maximus muscle strength using a handheld dynamometer. Data will be analyzed using SPSS version 21. Depending on data distribution, appropriate parametric or non-parametric statistical tests will be applied for both within-group and between-group comparisons. Ethical approval will be obtained before participant recruitment, written informed consent will be secured from all participants, confidentiality will be maintained, and participants will retain the right to withdraw from the study at any stage. The findings are expected to clarify whether a biomechanically integrated rehabilitation approach incorporating kinetic chain training provides greater improvements in pain, shoulder mobility, muscle strength, scapular function, and disability than conventional shoulder rehabilitation alone, thereby strengthening the evidence for comprehensive physiotherapy management of Subacromial Pain Syndrome.