Fig. 10. (A) Lag time between EMG onset and when lateral flexion was maximally convex on the side of muscle activity. (B) Lag time between EMG offset and when lateral flexion was maximally concave on the side of muscle activity. (C) Phase shifts between EMG onset and when lateral flexion was maximally convex on the side of muscle activity. (D) Phase shifts between EMG offset and when lateral flexion was maximally concave on the side of muscle activity. Values of zero for both phase shifts indicate muscle activity during the entire time of fiber shortening. Note that the magnitude of both phase shifts increased significantly with increased viscosity.