Chronic low back pain, which individuals have difficulty coping with in the modern age and is one of the most common reasons for applying to health institutions, has important consequences for individuals and society. Approximately 80% of individuals experience low back pain throughout their lives, and 10-20% become chronic. Low back pain causes varying degrees of restrictions in individuals' daily living activities, modification or reduction of movements due to pain. This situation causes the pain to continue and causes the functional level to decrease in individuals with low back pain. There are many approaches to the treatment of chronic low back pain, and among these, exercise treatments have been shown to be effective in reducing pain and improving functionality. Spinal stabilization exercises, which have an important place among current exercise approaches for chronic low back pain, ensure the formation of a neutral position in the spine by activating the core muscles consisting of multifidus, transversus abdominis, diaphragm and pelvic floor muscles. Perception of neutral position is provided and applied in daily living activities. In this way, pain is reduced and functionality increases by providing appropriate loading. What kind of changes occur in the core muscles due to the strengthening of the core muscles as a result of spinal stabilization exercises is an important question that needs to be clarified scientifically. It is possible to observe the mechanical changes occurring in the core muscles with shear wave elastography, which has been frequently used in clinical research and practice in recent years. However, in the detailed literature review, no scientific studies were found that evaluated what level of exercise intensity produces optimal changes in the muscle and the correlation of these changes with pain and functional improvement. In this study, where different intensities of exercise will be applied, the mechanical changes occurring in the core muscles before and after exercise will be evaluated with shear wave elastography and the aim is to evaluate the correlation of these changes with pain and pain

Patients with chronic low back pain who voluntarily participate in the study will be randomly divided into three groups. Physical and demographic information of the patients participating in the study will be collected. The number of patients who will participate in the study will be determined by the power analysis to be performed at the beginning of the study. Low back pain, disability index and pain sensitivity will be measured before treatment, after treatment and at the 12th week. Evaluation of core muscles with shear wave would be done at the beginning of treatment and at the 12th week. The exercise program will be implemented in the hospital under the supervision of a physiotherapist for 6 weeks, and the next 6 weeks will be followed as a home program. Participants in the first group will be included in the exercise program planned in detail below, 2 days a week, and those in the second group 4 days a week. Patients included in the third group will be followed with a home exercise program. The exercise program is planned to be 40 minutes and the first 5 minutes of the program will be warm-up and the last 5 minutes will be cool-down exercises.

In the first phase of the exercise program, patients will be placed in the hook position and contraction of the transversus abdominis muscle and multifidus muscle will be taught. Then, patients will be asked to perform exercises that enable the activation of other muscles of the body while maintaining the contraction of the transversus abdominis and multifidus muscles, and these exercises will be progressed from easy to difficult exercises. During exercise, the activation of the patients' spinal stabilizer muscles will be kept under constant control and necessary warnings will be made in this regard. Exercises will initially start with 8-10 repetitions and gradually increase to 20 repetitions. All exercises will be performed in 2 sets and there will be 30 seconds of rest between sets.

Inclusion Criteria:

• Chronic low back pain for at least 3 months.
• Not having participated in any physiotherapy or exercise program in the last month.
• Patients with informed consent

Exclusion Criteria:

• Malignancy
• Severe osteoporosis
• Arthritis
• Bone diseases
• Pregnancy
• Diabetics
• Lumbar or lower limb surgery
• Rheumatological and inflammatory problems.