Figure 1.

Muscle thickness was calculated as the distance between the superficial aponeurosis [a(sup.)] and the deep aponeurosis [a(deep)] in the middle of the ultrasound image at a 90-degree angle from the deep aponeurosis, as indicated by the double-headed arrow. The fascicle angle was the positive angle between the deep aponeurosis and the line of the fascicle, as indicated by theta (θ) and corresponding arrows.