Abstract
The purpose of this study was to examine the reliability of ultrasound evaluation of muscle thickness and intensity of the rectus femoris (RF) and vastus intermedius (VI). The subjects were 10 healthy adult males whose 20 limbs had no orthopedic disease, and they were supposed to refrain from any vigorous physical activity during the study period. The RF and VI were measured by two examiners on two separate days. Intra- and inter-observer reliability was evaluated using intraclass correlation coefficient (ICC) and Bland-Altman analysis. The ICC in intra-observer reliability of muscle thickness is 0.84 for the RF and 0.78 for the VI, and of muscle intensity, 0.71 for the RF and 0.88 for the VI. Ninety-five percent (95%) confidence intervals of minimal detectable change (MDC95s) for intra-observer reliability of muscle thickness are 0.23cm for the RF and 0.32 cm for the VI, and of muscle intensity, 18.17 a.u. for the RF and 13.74 a.u. for the VI. The MDC95s for inter-observer reliability of muscle thickness are 0.26 cm for the RF and 0.29 cm for the VI, and of muscle intensity, 20.21 a.u. for the RF and 13.52 a.u. for the VI. The results suggest that ultrasound imaging is a reliable technique for examining muscle thickness and intensity of the RF and VI.
