Relationship Between Central Sensitization and Clinical Features in Plantar Fasciitis

Pressure pain threshold is defined as the minimal pressure level that causes pain. The measurement will be applied twice for each region with a 1-minute interval, and the average of these applications will be recorded. A trial test will be conducted on the patient before the actual test. Pressure will be applied to selected points with a pressure algometer until pain is induced, and the test for that area will be terminated when the patient feels pain.

The measurement will be taken from the calcaneus bone (the starting point of the plantar fascia) and from the forearm, which is a distant, painless, and unrelated area, using the Wagner manual pressure algometer (1 cm² probe-10 kg/20 lb). The reliability of the measurement in these areas has been demonstrated.

Pain severity will be evaluated using a scale rated from 0 (no pain) to 10 (unbearable pain). Participants will be asked to rate the pain felt with the first step after waking up in the morning and the average pain level over the past week.

Physical Component Summary and Mental Component Summary

The Foot Function Index is a self-report-based scale developed to evaluate the effects of foot and ankle-related problems on pain, functional limitation, and daily life activities in individuals, with its validity and reliability demonstrated. AFI consists of three sub-dimensions: pain, disability (functional limitation), and activity limitation. The scale allows individuals to evaluate foot-related problems they have experienced recently in the context of daily life activities. Each sub-dimension and total score reflect the level of impairment in foot functions. Increasing AFI scores indicate that the severity of foot pain and the limitations in foot functions have increased, thereby negatively affecting foot-related quality of life. AFI is widely used in clinical and research settings to evaluate the functional effects of foot pathologies.

It is a valid and reliable self-report scale developed to assess individuals' exaggerated negative thoughts and emotional responses toward their pain experience. The scale measures cognitive and emotional responses that occur during or following pain and consists of three sub-dimensions: rumination (excessive focus on pain), magnification (exaggeration of the threatening consequences of pain), and helplessness.

It is a valid and reliable self-report scale developed to assess individuals' fear and avoidance behaviors toward movement and physical activity. The scale measures the level of fear of movement (kinesiophobia) that develops based on the belief that pain will reoccur or worsen.

The central sensitization scale is a tool used to assess the hypersensitivity of the central nervous system. This scale includes questions that examine individuals' pain perception and its effects on daily life to detect the effects of central sensitization, which are generally observed in chronic pain conditions. The scale evaluates how individuals perceive pain in response to physical contact or other stimuli (pain sensitivity), changes in their sensitivity to heat, cold, or pressure (sensory changes), how the persistence of pain affects their daily activities, and the impact of pain on their emotional state (anxiety, depression, etc.).

In the study, the evaluation with ultrasound will be conducted while the participants are in a prone position on the examination table, with their feet hanging off the table and in a dorsiflexed position. A linear probe will be placed longitudinally over the medial tubercle of the calcaneus to ultrasonographically examine the plantar fascia thickness (PFT). PFK will be measured 1 cm distal to the calcaneus attachment point. A PFK of 4 mm or greater will be considered evidence of fasciitis. It has been shown that this measurement technique has good intra-rater reliability. The Sonosite M-Turbo device will be used for ultrasonography and will be performed by a physical therapy and rehabilitation specialist with 10 years of experience.

It is a 14-item self-report scale that quickly, reliably, and independently of medical conditions assesses patients' anxiety and depression symptoms over the past week.

The range of motion of ankle dorsiflexion will be evaluated under load. The participant will be asked to keep their heel in contact with the ground and move their knee toward the wall, and the maximum distance between the thumb and the wall will be recorded in centimeters.

The participant's foot will be observationally scored based on six anatomical criteria in a standing natural posture, and the total score will be recorded.