High-Intensity Laser Therapy for Trapezius Myofascial Pain Syndrome: Effects on Pain, ROM, Function, and Depression A Four-Phase Development, Validation, and Evaluation Study

Myofascial pain syndrome of the trapezius muscle is a common cause of chronic neck and shoulder pain associated with functional limitation and psychological distress. Although High-Intensity Laser Therapy is increasingly used in clinical practice, high-quality evidence regarding its long-term effects and optimal treatment parameters is limited.

This double-blind, randomized, placebo-controlled trial will enroll 104 adults with clinically diagnosed trapezius myofascial pain syndrome. Participants will be randomly assigned to receive either optimized High-Intensity Laser Therapy or sham laser treatment. Outcomes will be assessed at baseline, immediately after the intervention, and at 16-week follow-up. This study aims to provide evidence for a standardized, patient-centered HILT protocol suitable for routine clinical practice.