Immediate effects of muscle energy technique on flexion relaxation phenomenon among individuals with non-specific low back pain.

This is a single-arm interventional study conducted to assess the immediate effects of Muscle Energy Technique (MET) on the Flexion Relaxation Phenomenon (FRP), pain intensity, and lumbar range of motion in individuals with non-specific low back pain (NSLBP). NSLBP is commonly associated with altered muscle activation, pain, and limited mobility. The FRP, which refers to a normal reduction in lumbar muscle activity during full trunk flexion, is often absent in people with low back pain.

The study will include 19 participants aged 18 to 60 years who report a pain score greater than 3 on a 0 to 10 scale and have difficulty bending forward. Individuals with acute or radiating pain, spinal deformities, tumors, previous trauma or surgeries, or diagnosed spinal conditions will be excluded.

Participants will first undergo a baseline assessment using surface electromyography (EMG) to record lumbar muscle activity during forward bending. Lumbar range of motion will be measured using the Back Range of Motion (BROM) II device, and pain will be rated using the Numeric Pain Rating Scale. Then, MET will be applied to the lumbar erector spinae muscle, involving isometric contractions followed by stretching, repeated 5 to 7 times.

After the intervention, the same assessments (EMG, range of motion, and pain) will be repeated immediately. This study is conducted at the Physiotherapy Department, Kasturba Hospital, Manipal. The findings may help support the clinical use of MET in improving function and managing pain in NSLBP.