The purpose of the study is to investigate whether Gua sha is an effective modality for relieving chronic low back pain specifically in the aged population by comparing the baseline measures of pain intensity, self-perceived disability, back range of motion, back local muscle stiffness, depression, sleeping quality, quality of life, biomarkers measurement, and analgesic intake on days 1 and 7 after a single session of Gua sha treatment. In addition, the investigators are going to compare between Gua sha and hot pack treatments for the above parameters.

Subjects will be randomized to receive firstly either one of the treatment arms, and then crossed over to receive another arm after 30 days washing out period. It is expected that Gua sha is 1) effective in reducing the intensity of chronic low back pain in the elderly; 2) effective in helping one or more outcome measures in this study and 3) more effective on relieving the low back pain than hot pack in terms of the outcome measures in this study.

Inclusion Criteria:

• Age 60 or above
• Self-reported painful restriction of lumbar spine mobility for at least 3 months or self-reported low back pain on at least 5 days a week for at least 3 months
• Have pain intensity score 40 or above on a 100mm Visual Analog Scale (VAS) at baseline

Exclusion Criteria:

• Prior history of radiculopathy or spinal stenosis or spinal fusion or failed surgery syndrome
• Having radiating pain below the knee
• Received the following surgery at the region of treatment in the past 12 months laminectomy, laminotomy or discectomy
• Serious illness (e.g. malignancy)
• Having wounds or skin lesions at the region of treatment
• Having blood pressure at140/90 mmHg or above at baseline
• Having Body Mass Index (BMI) at 18.5 or lower at baseline (as calculated by the weight in kilograms divided by the square of the height in metres (kg/m2)
• Having active psychiatric disorders, significant mood disorder or dementia