Effects of Vibration-Based and Instrument-Assisted Myofascial Interventions on Proprioception, Pain, Functional Disability, and Quality of Life in Individuals with Subacromial Impingement Syndrome: A Randomized Controlled Trial

Abstract Objective: To compare the effects of adding percussion massage therapy (PMT) or instrument-assisted soft tissue mobilization (IASTM) to conventional physiotherapy on joint position sense (JPS), shoulder range of motion (ROM), pain, disability, and rotator cuff–related quality of life in individuals with subacromial impingement syndrome (SIS). Design: Single-blinded randomized control trial. Methods: Forty-two participants with MRI-confirmed SIS completed a 4-week intervention and were analyzed (n=14/group). All groups received a conventional physiotherapy programme; the PMT and IASTM groups additionally received their respective interventions 3 times/week. Primary outcomes were JPS in shoulder flexion and abduction assessed using the Becure Extremity ROM system. Secondary outcomes included ROM (flexion, abduction, internal/external rotation), pain intensity (VAS-resting and VAS-activity), disability (DASH), and quality of life (RC-QoL). Between-group post-intervention comparisons used ANCOVA adjusted for baseline values. Results: All groups showed significant pre–post improvements (p≤0.047). After adjustment, a significant between-group effect was found for JPS in flexion (F=5.76, p=0.007, η²p=0.23), with greater improvements in PMT and IASTM versus conventional therapy (PMT vs CT p=0.021; IASTM vs CT p=0.004), and no difference between PMT and IASTM. JPS in abduction did not differ between groups (p=0.169). Significant between-group effects were observed for ROM, VAS (resting and activity), DASH, and RC-QoL (all p