Effect of Visceral Manipulation Versus Integrated Neuromuscular Inhibition Technique in Shoulder Impingement Syndrome

ABSTRACT Background and Purpose Shoulder pain during daily activities is a common musculoskeletal complaint affecting individuals across all age groups. Among its causes, Shoulder Impingement Syndrome (SIS) is one of the most prevalent. This study aimed to compare the effects of Visceral Manipulation (VM) and Integrated Neuromuscular Inhibition Technique (INIT) on pain intensity, shoulder function, and range of motion (ROM) in patients with upper trapezius trigger points associated with SIS, while considering the proposed role of VM in modulating musculoskeletal conditions through viscerosomatic interactions. Methods This randomized controlled trial included ( n = 75) patients aged 20–40 years with SIS and trigger points in the superior trapezius region were recruited. Participants were randomly assigned to three groups. Group A ( n = 25) received VM combined with traditional physical therapy modalities, including Transcutaneous Electrical Nerve Stimulation (TENS), hot pack application, ultrasound therapy, and therapeutic exercises. Group B ( n = 25) received INIT in addition to the same traditional physical therapy regimen. Group C ( n = 25), the control group, received only traditional physical therapy. Interventions were delivered over a 4‐week period, and all outcomes were reassessed immediately following completion of the intervention. All participants were assessed using the Visual Analog Scale (VAS), pressure algometer, standard goniometer, and the Shoulder Pain and Disability Index (SPADI). Results Post‐treatment analysis revealed statistically significant improvements across all groups in pain intensity, shoulder flexion and abduction range of motion (ROM), and functional level (SPADI) ( p < 0.001). Group A (VM) and Group B (INIT) showed greater reductions in VAS scores (MD = 3.96 and 4.00, respectively; p = 0.001), increases in pressure pain threshold (PPT) (MD = 6.88 and 7.34 lb; p = 0.001), and improvements in shoulder abduction (MD = 98.40° and 99.68°; p = 0.001) and flexion ROM (MD = 103.48° and 103.16°; p = 0.001) compared to Group C. SPADI scores decreased significantly in Groups A and B (MD = 27.24 and 23.40; p = 0.001), indicating enhanced functional recovery. Between‐group comparisons confirmed that Groups A and B were significantly superior to Group C ( p < 0.01), with no significant difference between Groups A and B ( p > 0.05). Discussion These findings should be interpreted cautiously, as the exploratory nature of the comparison and the limited evidence base supporting VM preclude definitive conclusions regarding its conceptual or mechanistic superiority compared to standard physiotherapy alone in managing pain, improving shoulder function, and increasing ROM in patients with upper trapezius trigger points associated with SIS. Trial Registration CkinicaTrials.gov ( https://clinicaltrials.gov/study/NCT06271720 )