To investigate the effects of short-term and medium-term monochromatic infrared energy therapy on patients with chronic low back pain (LBP) according to the International Classification of Functioning, Disability and Health.

Methods：70 participants with chronic LBP will be included. Participants received six 40-min sessions of hot pack therapy combined active or placebo monochromatic infrared energy therapy over the low back (wavelength = 890 nm, radiant power output = 6.24 W, power density = 34.7 milliwatt/cm2 for 40 min, total energy 83.2 J/cm2) followed by 20-min supervised therapeutic exercise, for 3 times per week for a 4-week duration. Patients will be assessed at before treatment and follow-up assessments, including after 2 week of treatment; after 4 weeks of treatment; and 1 and 3 months, respectively, after treatment is terminated.

Main Outcome Measures: Patients will be assessed periodically with pain, Multidimensional Fatigue Inventory, postural stability (using the postural stability evaluation system: Biodex Stability System), and Fear-Avoidance Behavior Questionnaire.

Inclusion Criteria:

participants with chronic low back pain

Exclusion Criteria:

1. low back pain accompanied by specific pathological conditions, such as an infection,inflammation, rheumatoid arthritis, fracture, or tumor;
2. a self-reported history of malignancy, vertigo, stroke, or other condition that may impair postural stability;
3. a history of low back surgery with an implant;
4. pregnancy or plans to become pregnant during the course of the study;
5. having received concurrent treatment for low back pain by another health care professional