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Fig. 2. A timing histogram relating the timing of electromyogram (EMG) activity,
muscle length change, muscle force production and kinematic data for an
individual bird flying at 7 m s-1. The zero time is set to the time
at which maximum force occurred, which corresponds to mid-downstroke. The bars
on each rectangle indicate standard deviation. Additional data on the
variation across speeds in the relationship between EMG onset time, muscle
shortening and force production are given in
Table 2.