Overview

This randomized, single-blind, placebo-controlled clinical trial aims to investigate the immediate physiological effects of a single session of electroacupuncture (EA) on neck muscle stiffness in individuals with chronic neck pain. While acupuncture is a widely used complementary therapy for musculoskeletal pain, high-quality, objective evidence demonstrating its immediate effects on muscle biomechanics remains limited. This study will utilize Shear Wave Elastography (SWE)-a non-invasive, objective ultrasound-based technology-to measure these changes.

Adult participants aged 18 to 65 with non-specific chronic neck pain (lasting

≥ 3 months) will be randomly allocated into one of two groups:

1. True Electroacupuncture (EA) Group: Participants will receive a 20-minute session of active electroacupuncture with comfortable electrical stimulation at specific neck and tender points.
2. Sham Acupuncture (Placebo) Group: Participants will receive a 20-minute session of non-penetrating sham acupuncture with a deactivated electroacupuncture device to ensure participant blinding.

The primary objective is to evaluate immediate changes in the stiffness of the upper trapezius muscle, measured objectively via SWE (as Young's Modulus in kPa) before and immediately after the intervention. Secondary objectives include assessing immediate post-treatment changes in subjective pain and stiffness (Visual Analogue Scale), Pressure Pain Threshold (PPT), and active Cervical Range of Motion (CROM), alongside a 7-day post-intervention follow-up questionnaire on neck function.

Eligibility

Inclusion Criteria:

1. Aged 18-65 years
2. Chronic non-specific neck pain persisting for ≥3 months
3. Average pain intensity ≥3 on a 0-10 Numeric Rating Scale over the past week
4. Pain primarily located in the posterior cervical region, which may radiate to the upper trapezius muscles
5. Able to provide informed consent and sufficient language proficiency to complete questionnaires

Exclusion Criteria:

1. Specific pathological causes for neck pain (cervical radiculopathy or myelopathy, fracture, infection, tumour, systemic rheumatic disease)
2. History of neck or shoulder surgery
3. Contraindications to acupuncture (severe needle phobia, bleeding disorders, pregnancy)
4. Received acupuncture or other physical therapy for neck pain within the past 6 months