This study will be conducted to investigate the correlation between the flexibility of hip muscles; hip flexors (iliopsoas, rectus femoris), hip extensors (hamstring), hip internal rotators, hip external rotators, hip adductors and hip abductors with pain intensity and disability level among patients with chronic nonspecific low back pain

Low back pain is considered the primary cause of disability worldwide. Low back pain is pain located at the area from the last ribs to the gluteal region with or without radiation to the lower limbs. Low back pain is associated with substantial economic burden, resulting from healthcare expenses, reduced productivity, insurance costs and sick leaves.

It was reported that limitation of hip range of motion of low-back pain patients was significantly different from that of healthy person. Due to the anatomic proximity and muscle connections, a number of studies have investigated the relationship between hip mobility and episodes of low back pain. From biomechanical point of view limited hip range of motion is compensated by hypermobility of the lumbar region thus generating overload with repetitive compensatory movements in the back.

Patients with non-specific low back pain demonstrate alteration in hip muscles flexibility. This relationship is important because the hip muscles act as an important link between the lower limbs and the trunk exerting forces from the lower limbs to the spine as well as from the spine. Any flexibility limitations of hip muscles not only decreases the range of motion but can also cause excessive mechanical stresses to lumbar spine during particular movement, thus affecting gait and other functional movements.

Up to the author's knowledge, there is few studies that investigates the correlation between the flexibility of all hip muscles and pain intensity and disability level in nonspecific low back pain patients. Therefore, this study aims to assess the correlation between the flexibility of hip muscles; hip flexors (iliopsoas, rectus femoris), hip extensors (hamstring), hip internal rotators, hip external rotators, hip adductors and hip abductors with pain intensity and disability among patients with 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.

50 patients with chronic non specific low back pain from both gender will participate in this study