This study which was planned to investigate the factors affecting m. erector spinae (ES), m. multifidus (MF), m. psoas major (PM) and m. quadratus lumborum (QL), which stabilize the lumbar region in the case of disc herniation. In this study, the effects of disc herniation, herniation severity, age, and spinal biomechanics were investigated.

This study was carried out on 330 individuals with and without lumbar disc herniation. All individuals were divided into 3 groups according to their age. The inclusion criteria: Having only disc degeneration and not having any other neurological or orthopedic disease. Patients who had previous spinal surgery, patients with lumbar scoliosis, spondylolisthesis or structural defect in the sacrum were excluded from the study.

Inclusion Criteria:

• Having only disc degeneration and not having any other neurological or orthopedic disease. Patients who had previous spinal surgery, patients with lumbar scoliosis, spondylolisthesis or structural defect in the sacrum were excluded from the study.

Exclusion Criteria:

• Patients who had previous spinal surgery, patients with lumbar scoliosis, spondylolisthesis or structural defect in the sacrum were excluded from the study.

Patients without disc herniation, severe disc degeneration and spondylolisthesis were also withdrawn from the System and included in the control group. 80 individuals with aged between 20-70 years included control group.

This study was planned to investigate the factors affecting muscle which stabilize the lumbar region in the case of disc herniation.