Acute Effects of Therapeutic Ultrasound on Passive Muscle Stiffness and Pain in Patients With Neck Pain

This study will test whether one session of therapeutic ultrasound can immediately reduce muscle stiffness and pain in adults with neck pain. Participants aged 18-50 years who report neck pain of at least 3 out of 10 will be randomly assigned to one of two groups: (1) active ultrasound or (2) sham ultrasound. Both groups will receive the same 10-minute procedure with the probe moved slowly over the painful neck muscles; however, the sham device will not deliver ultrasound energy. Before and right after the session, we will measure passive muscle stiffness at standard points on the neck and shoulder muscles using a handheld device and will record pain intensity on a 0-10 scale. We will also record the Neck Disability Index on the same day. The main question is whether active ultrasound produces a larger immediate decrease in muscle stiffness than sham. We will also examine changes in pain and neck function. The session is performed by trained physiotherapists in a clinic setting. Potential risks are minimal (such as temporary warmth or mild skin redness). There is no cost to participate. Results may help guide safe, non-drug treatment options for neck pain.