Fear-Avoidance Beliefs and Physical Function in Patients With Lumbar Disc Herniation

Lumbar disc herniation is one of the most common causes of low back pain and is associated with substantial functional limitations and reduced quality of life, particularly among working-age individuals. Displacement of disc material toward the spinal canal may result in mechanical compression and inflammation of the nerve roots, leading to pain, restricted movement, and reduced functional performance. The course of low back pain cannot be explained solely by biomechanical and anatomical factors. Psychosocial factors also play an important role in symptom persistence and functional outcomes. Within this context, the fear-avoidance model provides an important theoretical framework, suggesting that individuals may develop fear of movement and avoid physical activities because they believe these activities may increase pain or cause further injury. Over time, avoidance behaviors may contribute to physical deconditioning, reduced muscle function, and increased functional impairment. The Fear-Avoidance Beliefs Questionnaire is commonly used to assess individuals' beliefs regarding the relationship between pain, physical activity, and work-related activities. Higher levels of fear-avoidance beliefs have been associated with greater pain severity, increased disability, and poorer physical performance in individuals with low back pain. Trunk muscle endurance plays a key role in maintaining spinal stability. Adequate endurance of the paraspinal and abdominal muscles supports mechanical stability of the spine and contributes to the safe performance of functional movements. The Biering-Sørensen Test and plank test are commonly used to assess trunk muscle endurance in clinical and research settings. The Biering-Sørensen Test evaluates the endurance of the trunk extensor muscles, whereas plank-based tests assess the endurance of the anterior and lateral trunk musculature. Functional impairment in individuals with low back pain can be evaluated using the Oswestry Disability Index, a self-reported questionnaire that assesses limitations experienced during activities of daily living. Functional mobility and performance may also be evaluated using the Timed Up and Go test, which involves standing up from a chair, walking a short distance, turning, returning to the chair, and sitting down. This test reflects mobility, dynamic balance, and functional performance during daily activities. Postural control and balance may also be affected in individuals with low back pain. Reduced static balance performance can negatively influence functional activities and mobility. The Single-Leg Stance Test is a practical clinical measure used to assess postural stability and static balance. Although previous studies have examined associations between psychosocial factors and functional status in individuals with low back pain, studies evaluating the relationship between fear-avoidance beliefs, trunk muscle endurance, balance, and functional performance together remain limited. Identifying these relationships may contribute to the development of more comprehensive rehabilitation programs for individuals with lumbar disc herniation.

Inclusion Criteria: * Aged between 18 and 65 years * Clinically and/or radiologically diagnosed with lumbar disc herniation * Presence of low back pain for at least 3 months * Sufficient cognitive capacity to understand and perform the assessment procedures * Ability to walk independently * Willingness to participate voluntarily and provide written informed consent Exclusion Criteria: * History of lumbar spine surgery * History of neurological disorders, such as stroke or Parkinson's disease * Vestibular disorders or severe balance impairment * History of orthopedic injury or surgery affecting the lower extremities * Presence of rheumatological disease * Pregnancy * Severe pain or an acute inflammatory condition that prevents completion of the assessment procedures