Fig.6. In vivo patterns of strain and activation in the biceps femoris (A) and vastus lateralis (B) during two strides of walking, trotting and galloping (trailing limb and leading limb). Dark shading represents the stance phase, and light shading represents the swing phase. Slightly different scales are used between muscles for both strain and voltage. Note that total shortening strain levels in the biceps femoris are reduced during galloping relative to other gaits. In addition, the vastus lateralis during most gaits is active (as prescribed by EMG activity) during lengthening, but exhibits very little shortening during this time. However, in the leading limb during galloping, vastus fascicles exhibit more shortening when active.
