Back or neck problems often begin with an injury and often include a muscle injury. Injury of muscle fibers can occur due to trauma, disease, myotoxic agents, inflammatory processes, and intense exercise. The level of muscle injury in low back or neck problems is unknown. However, the relationship between muscle injury and pain has been studied intensively.

Injury to skeletal muscles occurs when muscle activation begins abruptly and rapidly with muscle lengthening. Muscle pain that occurs with eccentric exercise peaks 24-48 hours after the exercise. Studies on this subject have generally focused on muscle fatigue, changes in the physiological structure of the muscle, and which muscle fiber types are injured more. Experimental studies focused on the results of skeletal muscle injury with early activation of the muscle during eccentric exercises. For example, it has been shown that mechanical changes in the tibialis anterior muscle occur in the first 5-7 minutes of exercise during eccentric exercise. Studies on the back and neck muscles are rare, and it has been stated that fatigue in these muscles plays an active role in the mechanism of injury. It is very difficult to accept this view directly, because there are different types of muscle fibers in the lower back and neck muscles. In terms of low back and neck pain and muscle injury, specific studies on muscle fiber types are required. In addition, muscle strength together with pain can change the load distribution to anatomical structures. However, muscle activity alters spinal stability and kinematics. It has been found that the M. Sternocleideomasteideus (M.SCM) muscle shows 5%-10% elongation tension during muscle activation, along with retraction in whiplash injuries. In deep muscle groups, this rate varies between 10% and 20%. It is not known to what extent the architectural features of the muscle change with these muscle tensions and to what extent the injury occurs when active extension occurs. It is clear that the relationship between muscle pain and injury should be examined in terms of biomechanical modeling, muscle architecture and outcomes.

Muscle length, fiber length, pennation angle, and physiological cross-sectional area (PCSA) values of many muscle groups, primarily the M.SCM and M.Transversus Abdominus muscles, were analyzed in healthy individuals. However, it is not known how it changes in individuals with low back or neck pain. For this reason, if the architectural features of the cervical and lumbar region muscles can be determined, since they are the muscles that are most affected by low back and neck problems and then exercised the most by physiotherapists, the relationship between injury and pain can be examined and correct muscle function can be achieved. The emergence of different values from healthy muscle architecture will be valuable in terms of correct exercise planning and proper function in individuals with low back and neck problems. The aim of working with this idea is to evaluate the architectural features of the cervical and lumbar region muscles in individuals with problems characterized by low back and neck pain.

Inclusion Criteria:

• Patients with neck or low back pain
• Healthy Individuals
• Between the ages of 18-60,
• Being literate,

Exclusion Criteria:

• Cervical radiculopathy, thoracic outlet syndrome,
• Malignant condition,
• Having systemic diseases such as neurological, psychological, cardiovascular and loss of function due to these diseases,
• A history of surgery in the spine and upper extremity, including the cervical region, in the last 1 year period,
• Fracture in the spine and upper extremity, including the cervical region, with a history of inflammation,
• Acute infection,
• Continuing another rehabilitation program,
• Individuals who do not agree to participate in the study and do not give written consent will be excluded from the study.

Patients with neck or low back pain and healthy individuals will be included in to study.