Ultrasonographic measurements
Anterior thigh muscle thickness was measured by using a 5-12 MHz linear probe (Logiq P5, GE, Medical Systems, USA). Ultrasound (US) images were obtained without any compression by using adequate amount of gel, while subjects lied in supine position. The muscle thickness was measured in the axial view - at 50% level between the anterior superior iliac spine and upper pole of the patella. The measurement was taken between the outer fascia of rectus femoris and the periosteum of femur (Fig. 1). All measurements were performed (from the dominant side) by a physiatrist (MK) who is an expert in musculoskeletal US - with more than 10 years of experience. Thereafter, sonographic thigh adjustment ratio (STAR) was calculated via dividing the anterior thigh muscle thickness (mm) by body mass index (BMI).5