Correlation Between the Flexibility of Hip Muscles, Pain and Disability in Chronic Nonspecific Low Back Pain

Inclusion Criteria: * Chronic nonspecific low back pain for at least 3 months. * Age of the patient will range from 20 and 45 years. * Pain intensity of three or higher based on the visual analogue scale (VAS, 0-10 scale). * .Body Mass Index from 18-25 kg/m2. Exclusion Criteria: * spinal surgery, spinal or pelvic fracture. * ankylosing spondylitis or rheumatoid arthritis. * spondylolisthesis or spondylolysis, neurological disorders. * spinal inflammation or tumor. osteoporosis. * Continuous use of pain medications. * respiratory disease or heart disease. * Pregnancy.