Transcutaneous Electrical Nerve Stimulation (TENS) for the Treatment of Low Back Pain (LBP) in Adults

Inclusion Criteria: 1. Adults aged 18-65 years 2. Diagnosis consistent with myofascial low back pain (localized low back pain with a palpable taut band; referred pain and/or sensory changes near a specific trigger point; an identifiable tender spot within the taut band; mild muscle weakness and/or some limitation of joint range of motion) 3. Mild pain intensity at baseline (VAS \< 4 on a 0-10 scale) 4. Symptom duration \> 1 month 5. Able to understand the study procedures and demonstrate good compliance/cooperation 6. Written informed consent provided Exclusion Criteria: 1. Low back pain due to other causes, including but not limited to lumbar disc herniation, lumbar spinal stenosis, ankylosing spondylitis, spinal tumor, spinal tuberculosis, or spinal infection 2. Received physical therapy, interventional procedures, or medication treatment within 4 weeks prior to enrollment that may affect pain or function assessment 3. Systemic disease or organ dysfunction 4. Skin/soft tissue breakdown or infection at/near the planned treatment area 5. Use of sedative medications or opioid analgesics within 6 months prior to enrollment, or currently receiving other treatments that may affect study outcomes 6. Severe psychiatric disorder or inability to cooperate with study procedures 7. Pregnant or breastfeeding women