Pressure pain threshold measurements will be assessed using a pressure algometer, a gun-shaped apparatus with a 1-cm² rigid rubber probe held at a 90-degree angle to the body and then applying pressure at a constant rate of increasing pressure (30 kPa/s) until the patient's pain threshold is reached. The assessment will be performed bilaterally in 4 different regions, one assessment per anatomical region: trapezius muscle, elbows (lateral epicondyle), quadriceps femoris muscle, and knees (in the medial fat pad near the joint line). For each participant, the total mean pressure pain threshold measurements will be calculated and used for analysis. Sensitive points will be determined according to the guidelines of Okifuji et al. Previous studies have shown that assessing pressure pain threshold measurements in a limited number of regions provides a good estimate of overall sensitivity.

The Cognitive Exercise Therapy Approach Scale assesses the biopsychosocial status of patients with rheumatic diseases. The total score ranges from 0 to 120. Higher scores indicate a worse biopsychosocial status.

The original Tampa Kinesiophobia Scale was developed by Miller, Kopri and Todd in 1991, but was not published. Vlaeyen et al. republished the original scale, consisting of 17 questions, in 1995, with the permission of the researchers who developed it. TAS is a 17-question scale developed to measure fear of movement/re-injury. The scale includes injury/re-injury and fear-avoidance parameters in work-related activities.

Developed to identify patients' catastrophic thoughts or feelings about the pain they experience and their ineffective coping strategies, this scale is a thirteen-item Likert-type self-assessment scale. Each item is scored between 0 and 4. The total score ranges from 0 to 52. Higher scores indicate a high level of catastrophizing.

The Short Pain Inventory is a short, easy-to-administer assessment method that can be used to evaluate pain. It includes numerical rating scales from 0 to 10. In the Short Pain Inventory, the worst pain is defined as mild (1-4), moderate (5-6), and severe (7-10). It assesses the severity of pain, its localization, medical treatments for pain, and its impact on daily functions, and asks how much pain has decreased in the last 24 hours or the past week. Answering all questions takes a short time, approximately 5-10 minutes.

The Generalized Pain Index is an index that assesses a patient's pain in 19 regions over the past week. The Symptom Severity Scale consists of 3 questions: fatigue, difficulty thinking and remembering, and sleeplessness. The severity of each of these 3 complaints over the past week is scored using a scale from 0: no problem, 1: mild problem, 2: moderate problem, 3: severe problem.