RELATIONSHIP BETWEEN ULTRASONOGRAPHIC QUADRICEPS MUSCLE THICKNESS AND SARCOPENIA MARKERS (HANDGRIP STRENGTH, SARC-F) AND KINESIOPHOBIA IN STROKE PATIENTS

Overview

The aim of this study is to evaluate the relationship between ultrasonography-measured quadriceps muscle thickness and the sarcopenia markers SARC-F questionnaire and handgrip strength in patients diagnosed with ischemic stroke. In addition, the relationship between quadriceps muscle thickness and the level of kinesiophobia will be quantitatively assessed. This study is a cross-sectional clinical study conducted between August 1, 2025, and August 1, 2026, at the Physical Medicine and Rehabilitation Clinic of the University of Health Sciences İstanbul Physical Medicine and Rehabilitation Training and Research Hospital. Fifty volunteer participants with ischemic stroke and a lower-extremity Brunnstrom motor stage of 3 or higher, who presented to the clinic during the study period, were included. Bilateral quadriceps femoris muscle thickness, including the rectus femoris and vastus intermedius muscles, was measured using ultrasonography. The SARC-F questionnaire was used to assess sarcopenia risk, handgrip strength measurement was used to evaluate muscle strength, and the Tampa Scale for Kinesiophobia was used to determine the level of kinesiophobia. Motor recovery stage was assessed using the Brunnstrom Staging system; motor and cognitive independence were assessed using the Functional Independence Measure; walking independence was assessed using the Functional Ambulation Scale; and independence in activities of daily living was assessed using the Barthel Index of Activities of Daily Living. Because balance impairment, muscle weakness, and limited mobility are common after stroke, physical performance tests may be difficult to administer safely and consistently in this patient population. Therefore, the relationship between quadriceps muscle thickness and physical performance tests was not evaluated in this study. The Chair Stand Test, which requires repeated sit-to-stand movements as well as adequate balance and lower-extremity muscle strength, was also not included because it may increase the risk of falls in patients with limited mobility. This study aims to demonstrate the clinical potential of ultrasonography in the assessment of post-stroke sarcopenia and to support a more holistic approach to stroke rehabilitation planning that considers both physical and psychological factors.

Sarcopenia is a common consequence of stroke, resulting from immobility, decreased physical activity, and impaired neuromuscular control. This process particularly affects the lower extremity muscles, limiting physical independence and reducing the effectiveness of rehabilitation. The structural properties of lower extremity muscles are considered an important determinant of a patient's functional capacity, and the quadriceps femoris muscle plays a central role in essential motor tasks such as walking and transferring, given its involvement in knee extension and hip flexion. Ultrasonographic assessment of quadriceps muscle thickness offers a non-invasive and practical method for obtaining quantitative and objective data on muscle morphology, providing a clinically valuable advantage over more resource-intensive imaging modalities such as DXA, bioelectrical impedance analysis (BIA), CT, or MRI. While handgrip strength and the SARC-F questionnaire are widely used as initial screening tools for possible sarcopenia, a definitive diagnosis requires muscle mass quantification, for which ultrasonography has become an increasingly used method in recent years. This study does not classify patients according to sarcopenia status; instead, it evaluates the extent to which handgrip strength and SARC-F scores align with ultrasonographically measured quadriceps thickness. This relationship has been studied in other patient populations but remains less explored specifically in stroke survivors, which is why this population was selected. In addition to physical determinants of musculoskeletal health, psychological factors are also considered relevant. Kinesiophobia-an irrational fear of movement-is frequently observed after stroke and may limit participation in physical activity, reinforcing a cycle of inactivity and further muscle deterioration. This study therefore also examines the potential association between kinesiophobia and quadriceps muscle thickness in chronic stroke patients, aiming to provide clinically relevant insight into how muscle structure and psychological status may interact, and to support a more individualized and multidisciplinary approach to post-stroke rehabilitation planning.