Figure 2. Ultrasound image of the medial gastrocnemius and calculation of the medial gastrocnemius (MG) and the medial gastrocnemius–tendon unit (MTU) behavior. L_strike, L_e-m, L_m-t, L_p, and L_toe-off are the fascicle length of touchdown, the end of the early stance phase and the start of the mid-stance phase, the end of the mid-stance phase and start of propulsion phase, the end of propulsion phase and toe-off moment. L_max and L_min are the maximum and minimum fascicle lengths. L_MTUstrike, L_MTUtoe-off, and L_MTUmax are the length at touchdown, toe-off, and the maximum length of the medial gastrocnemius-tendon unit (MTU).