Soft Tissue Biomechanical Behavior During Acupuncture in Low Back Pain

Inclusion Criteria: Inclusion criteria for LBP subjects will be the following: 1. History of recurrent or chronic LBP as defined by Von Korff {Von Korff, 1992 #6777} {Von Korff, 1994 #6816} for a minimum of 12 months 2. Able to stand and walk without assistance 3. Able to understand and read English 4. Able to understand and sign a consent form. Subjects' LBP will be further defined as being recurrent or chronic LPB based on the number of days with symptoms over a period of one year. * Recurrent LBP will be defined as back pain present on less than ½ the days in a 12-month period, occurring in multiple episodes over a year. * Chronic LBP will be defined as back pain present on at least ½ the days in a 12-month period in a single or multiple episodes. Inclusion criteria for No-LBP subjects: Criteria for selecting No-LBP subjects will be: 1. No history of low back pain or any other chronic pain that has limited activities of daily living or work 2. A numerical current pain index of less than 0.5. No-LBP subjects will be matched for age, sex and subcutaneous tissue thickness with LBP subjects. Exclusion Criteria: For all subjects, exclusion criteria determined by history and physical exam will be the following: 1. Previous severe back or low extremity injury or surgery 2. Major structural spinal deformity (scoliosis, kyphosis, stenosis) 3. Ankylosing spondylitis or rheumatoid arthritis 4. Spondyloarthropathy or disc herniation 5. Spinal fracture, tumor or infection 6. Neurological deficit (weakness and/or sensory loss, decreased deep tendon reflexes suggesting nerve root compression, but not subjective symptoms of nerve root irritation (sciatica) 7. Neurological or major psychiatric disorder 8. Bleeding disorders 9. Corticosteroid or anticoagulant medication 10. Pregnancy 11. worker's compensation or disability case 12. In litigation for the LBP problem 13. Acute systemic infection 14. BMI greater than 23% or less than 32%. Preliminary testing has shown that individuals with a BMI of less than 23% have an insufficient depth of the subcutaneous and fat zone (Zone P) for data processing. Individuals with a BMI greater than 32% have a subcutaneous and fat zone (Zone P) thickness which is greater than the acupuncture needle length, which will not allow penetration of the muscle layer (Zone M). 15. Subjects will need to not take non-steroidal anti-inflammatory (NSAIDs) medication for 3 days prior to testing in order to avoid the potentially confounding acute effects of NSAIDs on connective tissue. 16. In addition, LBP subjects will be excluded if they are in an acute flare-up of LBP. Flare-up will be defined as short period (less than one week) when pain is markedly more severe than usual for that individual (at least 5 points above baseline on pain index).