Non specific chronic low back pain (LBP) is a debilitating disorder characterized by tremendous personal and socioeconomic impact, with long-term sick leave, low quality of life, and very high financial costs. Evidence suggests that patients with non specific LBP presented with altered muscle activity pattern when compare with healthy people. It has been reviewed that exercise therapy was effective for modulation of muscle dysfunction in chronic low back pain. However, there is a lack of objective assessment of the pain relief in low back pain rehabilitation. Clinical application of surface electromyography (EMG) may provide a quantitative and objective tool to evaluate the rehabilitation outcome in patients with non specific chronic low back pain before and after treatment.

Objectives: To verify the usefulness of surface electromyography (EMG) in low back pain (LBP) rehabilitation assessment.

Setting: Out-patient physiotherapy musculoskeletal rehabilitation

Participants: One hundred adults with non specific chronic low back pain (LBP) will be recruited.

Methodology: A prospective correlation study between clinical examination and electrophysiology assessment. This project will perform carefully with a definitive chronic low back pain (LBP). Firstly, we will compare the surface EMG features from patients with LBP to normal data. In addition, the changes in electrophysiology assessment will be compared with clinical assessment by Numeric Pain Rating Scale (NPRS). This allows us to verify the potential clinical application of surface EMG features in physiotherapy progress assessment.

Inclusion Criteria:

• One hundred persons with non specific low back pain will be recruited consecutively from the Specialist Outpatient Department (SOPD) of Physiotherapy Department of Queen Elizabeth Hospital. Subjects will be included in the study if they presented with symptom duration of greater than three months with no radiological abnormality detected.

Exclusion Criteria:

• All subjects should be able to provide informed consent and demonstrate sufficient ability to tolerate the experiment procedure to avoid aggravation of symptoms during the experiment procedures. Subjects will be excluded if they have any major orthopedic, neurological, circulatory or respiratory conditions, a history or family history of epilepsy, recent or current pregnancies, and previous surgery to the abdomen or back. The back pain history in the previous year will be documented for those eligible subjects.