Fig. 6. Summary histogram of the timing (mean ± S.D.) of muscle activation and strain recorded from the different regions of the pigeon pectoralis, together with total muscle force measured at the DPC. Time zero is defined relative to when the pectoralis exerts peak force, with the force histogram spanning the period of force development by the muscle. EMG histograms span from the mean onset to the mean offset of the EMG. Strain histograms span from the onset of muscle lengthening to the end of muscle shortening. The central bar within the strain histograms represents the time the muscle region reaches its peak length.