MRI scans reveal how massage changes back muscles in chronic pain

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Adult males or females (age ≥ 18 years) * Report chronic low back pain (≥3 months) (measured by patient history and clinical evaluation) * Pain intensity reported at baseline must be ≥4 on the pain VAS scale * Presence of myofascial pain features in the lumbar region (e.g., localized tenderness and/or trigger points identified by a qualified clinician/therapist) * Able to lie in supine and prone positions for study procedures * Be able to participate fully in all aspects of the study * Have understood and signed study informed consent Exclusion Criteria: * Pregnancy or breastfeeding * Patients with the inability to stay in a prone and supine position for the required procedure durations (e.g., ≥30 minutes at a time) * Any contraindication to an MRI exam, or severe claustrophobia that would prevent safe completion of the scan * Previous lumbar spine surgery or history of severe lumbar injury (e.g., fracture) that, in the investigation team's judgment, would interfere with participation or safety * Patients with known bleeding disorders or current therapeutic anticoagulation that would increase risk of bruising/bleeding with massage * Patients with skin conditions affecting the treatment area (e.g., rash, open wound, active dermatitis) or known allergy to any materials used during treatment (e.g., gels/cleaners), if applicable * Receipt of a new pain treatment within 3 days of the study visit (e.g., injection, ablation, spinal manipulation, massage/manual therapy) that could confound pre/post measures * Use of short-acting opioid analgesics or sedating medications within 24 hours of the study visit * Have an implanted device in or near the treatment area that could interfere with safe application of external pressure * Have used an investigational drug within 30 days of study enrollment * History of any major cardiovascular events including heart valve disease, ongoing angina, cardiac arrhythmias, congestive heart failure, acute coronary syndrome, stroke, transient ischemic attack, or peripheral vascular disease. * Clinically significant unstable neurologic or systemic illness that would preclude safe participation, as judged by the investigation team. * Surgical intervention for pain within 1 month prior to enrollment * Active infection, wound, or other external trauma to the areas to be treated * Have a known history of any condition or factor judged by the investigator to preclude participation in the study or which might hinder adherence * Inability to provide consent