Inclusion Criteria:  Group 1 90 Healthy Volunteers - age >40 years, no history of neck pain, back pain, or radicular pain in the previous six months, no history of chronic neck or back pain lasting more than three months, no history of spinal disease or surgery, no spinal deformity or lumbar spondylolisthesis, no history of hip or knee arthroplasty or other realignment surgery of the lower extremities, and no history of neuromuscular disorders.  Group 2 126 patients Clinical diagnosis of Lumbar degenerative disease  Exclusion Criteria:  Group 1 90 Healthy Volunteers  - pregnant  Group 2 126 patients  Neuromuscular diseases Arthritis Tumor A previous history of lumbar fusion surgery