Fig. 7. (A) Variation in peak muscle force and muscle strain rate as a function of flight speed. (B) Changes in the amplitude of muscle strain with speed (P<0.01; Table 2). Values represent interindividual means ± S.D. (N=5 for each speed). Pectoralis force, strain rate and strain amplitude vary similarly with speed, and the pattern of variation matches that found for muscle power output versus speed (Fig. 5).