2.5.3. Muscle Quantity and Quality Indexes 
To assess the muscle thicknesses of the anterior and posterior femoris muscles and the echo intensity of the rectus femoris muscle, we used a B-mode ultrasound device with 3.4–8.0 MHz linear-array probe (Vscan dual probe, GE Healthcare, Chicago, IL, USA). Ultrasound images consistently set the following parameters: frequency 8.0 MHz; gain 60 dB; depth 6–10 cm. All participants were scanned perpendicularly on the anterior and posterior thigh surfaces, halfway between the lateral condyle of the femur and the greater trochanter, in the anatomical standing position, with their arms and legs extended and relaxed. Three images of the anterior and posterior femoris muscles were obtained for each measurement site and stored on a personal computer. Images obtained from an ultrasound device regarding muscle thickness and echo intensity were analyzed using ImageJ (version 1.52a; National Institutes of Health, Bethesda, MD, USA), as previously reported [As indices of muscle function, 6-m normal walking speed, single-leg stand test, five times sit-to-stand test, and handgrip strength were assessed before and after each intervention, as previously reported [