Methods The study design was a randomized clini- cal trial. Ethical approval for this study was granted by the Research Ethics Committee of Tehran University of Medical Sciences (grant number 90-9-28-1992). Subjects were provided with information booklets explaining the purpose of the study and signed informed consent documents prior to participation. Subjects were free to with- draw from the study at any time. This study was conducted in Hazrat Rasool-e-Akram Hospital located in Tehran (Iran) between 2011and 2012. All measurements were tak- en before and after a 6-week intervention period. Subjects: A total of 98 subjects was ini- tially recruited from Hazrat Rasool-e- Akram hospital sports medicine and ortho- pedic clinics and judged to meet the criteria for the study. Twenty six subjects did not fulfill the inclusion criteria (Fig 1). Inclu- sion and exclusion criteria were assessed for each subject based on a clinical exami- nation performed by the first author. The inclusion criteria were as follows: (1) Male and female mentally fitted between the ages of 18 to 75 years; (2) Unilateral shoulder pain of more than one month localized (an- terior and/or anterolateral) to the acromion; (3) Tenderness to palpation of the rotator cuff tendons; (4) Positive impingement tests, or a painful arc of movement (60°– 120°) ;(5) Pain produced or increased dur- ing flexion and/or abduction of the symp- tomatic shoulder. All subjects tested positive for impinge- ment tests (which included the Hawkins, Neer, and Empty can tests) and underwent a full screening of cervical and shoulder ROM, resisted motions, and special tests. No single impingement test has 100% sen- sitivity or 100% specificity. Therefore, to correctly identify patients with shoulder
impingement, a combination of clinical tests is recommended. According to Ure et al. findings , multiple tests were able to cor- rectly distinguish SIS from other shoulder pathologies in 86% of cases(21-22). Exclusion criteria were as follows: (1) cervical or shoulder symptoms reproduced by a cervical screening exam; (2) abnormal results with reflex or thoracic outlet tests; (3) symptoms of numbness or tingling in the upper extremity; (4) pregnancy, or (5) a history of the followings: onset of symp- toms due to traumatic injury, glenohumeral joint dislocation, acromioclavicular joint separation, shoulder fracture, surgery on the shoulder, fibromyalgia, use of any treatment within three months. Main partic- ipants were 72 SIS patients who were ran- domly allocated into two groups: (1) Scapular Stabilization based Exercise Ther- apy group (ET) and (2) Physical therapy group (PT). Random allocation of the subjects was done by using a random number table and block random sampling; A: ET; B: PT (a block size of 4). Block Size: Block 1: AABB Block 2: ABAB Block 3: BBAA Block 4: BABA Block 5: ABBA Block 6: BAAB