Shoulder impingement syndrome (SIS) is the most commonly diagnosed shoulder disorder. In literature shoulder impingement is reported between 48% and 65% of all painful shoulder conditions.~The coordinated coupled motion between the scapula and humerus, the so-called scapulohumeral rhythm (SHR), is needed for efficient arm movement. Reduced scapular mobility reduces the acromio-humeral distance during arm abduction and therefore increases the risk for shoulder impingement syndrome.~Clinical prediction rules (CPRs) are tools designed to improve decision making in clinical practice by assisting practitioners in making a particular diagnosis, establishing a prognosis, or matching patients to optimal interventions based on a parsimonious subset of predictor variables from the history and physical examination.~HYPOTHESES:~Pain severity will not be predictor for treatment success in patients suffering from subacromial impingement syndrome treated with scapular training.~Scapular upward rotation angle will not be predictor for treatment success in patients suffering from subacromial impingement syndrome treated with scapular training.~Ratio of upper trapezius /serratus anterior isometric strength will not be predictor for treatment success in patients suffering from subacromial impingement syndrome treated with scapular training.~RESEARCH QUESTION:~Does pain severity, scapular upward rotation angle and upper trapezius/serratus anterior isometric strength ratio predict patient's esponse to scapular training in patients with subacromial impingement syndrome?
To investigate if pain severity, scapular upward rotation angle and upper trapezius/serratus anterior isometric strength ratio can predict patient's response to scapular training in patients with subacromial impingement syndrome.