Fig. 2. Representative recordings of muscle force, length and electromyographic (EMG) activity for lateral gastrocnemius (LG, above) and digital flexor-4 (DF-IV, below) during level running at 1.3 m s^-1, from one individual (bird 5). Shaded bars indicate the support phase of the locomotor cycle. Top, silhouettes of the bird show the phases of the stride for one cycle, with the recorded limb in black and the contralateral limb in gray.