Outcome measures

Primary outcome included 1.4 -point reduction in pain intensity at a 5-week period compared to the baseline [27] measured using a 10 cm VAS. Pain intensity ranges from 0 to 10, in which 0 = no pain at all and 10 = the worst pain possible. Patients were asked to sign the place on the VAS scale that corresponded to their pain level. This scale is a valid and common tool for measurement of pain intensity [28].

Secondary outcome of the study included a 13 -point decrease [25] in shoulder pain and dysfunction at a 5-week period compared to the baseline, assessed through Shoulder Pain and Dysfunction Index (SPADI). So a minimal reduction of 13 points in the SPADI was considered as Minimal Clinically Important Difference (MCID) regarding functional improvement perceived by the patients [29].

The SPADI is a self-administered questionnaire created to assess shoulder functional abilities. It consists of 13 items assessing two different areas. The first 5 items measure the pain, and the next 8 items assess patients’ disability. To answer the questions, subjects place a mark on a numbered scale ranging from “0 (for no pain and difficulty) to 10 (for maximum pain, or difficulty in function, so that the patient needs help)” for each question [30]. Validity and reliability of this questionnaire in Persian version has been confirmed in previous researches [31].

Using a goniometer, ROM of shoulder was evaluated in active and passive abduction, flexion, external rotation, and internal rotation. Validity and reliability of this measuring device has been demonstrated by other researchers [32].

Before and after the intervention, a blinded physiatrist assessed above-mentioned parameters.