Fig. 3. Patterns of hip (A,C,E) and knee (B,D,F) joint angle excursions from one individual at all gaits, in red, superimposed onto fascicle strain patterns of the biceps and vastus, respectively, in black. The right-hand y-axis corresponds to the joint angles, the left-hand y-axis to the strain. Stance and swing phases are shaded dark and light gray, respectively. Note how biceps fascicles generally shorten during hip extension and lengthen during hip flexion. Vastus fasicles are generally stretched during knee flexion and shorten during knee extension.