Homogeneity and reproducibility of in vivo fascicle length and pennation determined by ultrasonography in human vastus lateralis muscle

摘要

Introduction. - Evaluate reliability of ultrasound measure to estimate muscle architecture. Methods and results. - Ultrasound measurements were performed on the vastus lateralis muscle of 19 subjects. Test-retest measurements were performed at 10deg and 100deg of knee flexion, at rest and at 40% of MVC. Muscle thickness (MT) was measured on both sides and at the centre of the image. The fascicle pennation angle (6) was estimated as the angle between a fascicle and the deep aponeurosis and as the average of the two angles between the same fascicle and its insertion into the aponeuroses. Fascicle length (FL) was estimated under the assumption of linearity as FL = M T * sin 0~(-1). The most important factor influencing the measurement reproducibility of the pennation angle (9) was the knee joint angle. For MT, reproducibility was higher during contraction at 10deg of knee flexion. The different methods of estimation provided a good level of reproducibility for 9 and MT. The estimation of the fascicle length was better for a 10deg knee joint angle at 40% of MVC. Conclusion. - Reproducibility of muscle architecture from ultrasonic measurements was better for a shortened position and contracted muscle, but poorly or not influenced by the method of calculation.