Low back pain (LBP) is considered one of the most common musculoskeletal disorders in modern society, resulting in substantial costs to society. Factors associated with the development of low back pain include poor posture, strenuous work with the body, inadequate non ergonomic work and traumas.

Rotation movement pattern of the lumbar spine in different positions is essential aspect in understanding the LBP Pathophysiology. Rotation coupled with forward bending (flexion) is a dominant factor which could increase the risk LBP and disc prolapse. There is also a decline in range of motion (ROM) of rotation in forward bending (flexion) compared to neutral position during sitting and standing.

In addition,lumbar rotation movement patterns differ in population with LBP compared to asymptomatic individuals. Healthy individuals exhibit rotation accompanied by consistent coupled movement patterns of lateral bending in the opposite direction at thr upper levels, and by lateral bending in tge same direction at the lower levels . while Chronic LBP patients exhibit non consistent patterns altered from those of the normal population.

According to the investigators, Kinematic measures of velocity and acceleration of lumbar rotation in neutral position and full flexion in sitting and standing did not studied yet. Evaluating these parameters, in addition to ROM and plains evaluation in the LBP population, compared to healthy population will contribute a lot in understanding this issue.

Inclusion Criteria:

• non specific chronic LBP (three months or more)
• Insured by Clalit Health Care Services
• Signed informed consent

Exclusion Criteria:

• History of spinal /pelvic surgery.
• Trauma or fracture of spine /pelvis.
• Inflammatory diseases of spine.
• radiation to lower extremities .
• Neurological disease.
• malignancy disease. structural deformity of vertebral structures(scoliosis, kyphosis).

Individuals referred to physiotherapy for LBP