Prognostic Factors of Disabling Low Back Pain in Patients With Chronic Low Back Pain

Inclusion Criteria: * adults between 18 and 60 years old * nonspecific low back pain : pain located between the twelfth rib and the inferior gluteal fold for which no specific source of pain could be identified * chronic low back pain : pain present for 12 weeks or more, and included both constant and recurrent patterns of pain * able to read and understand French Exclusion Criteria: * History of surgery or major trauma to the spine * Current use of medication known to impair physical effort and pain perception * Lumbar scoliosis of more than 20° * Collagenosis, severe osteoporosis * Neuromuscular disease * Malignant tumor * Non-controlled hypertension * Infection * Radiculopathy * Progressive neurologic defect * Myelopathy * Lumbar disc hernia * Pregnancy * Active lower body injury and/or severe and disabling pain limiting the capacity to undergo the evaluation.