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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.