Fig. 3. Mechanical properties of galloping animals at the trot—gallop transition speed plotted versus body mass on logarithmic scales. Open circles are experimental values, and filled circles are model predictions. Least-squares regression lines are fitted to the model results (see text for equations). (A) Stride frequency. (B) Hindlimb excursion angle, the maximum angle swept by a line drawn from the head of the femur to the toe. (C) Forelimb duty factor, the percentage of a stride period in which a forelimb contacts the ground, and peak vertical force per body weight. Animal data are adapted with permission from (A) Heglund et al. (1974), (B) McMahon (1975) and (C) McMahon (1977). Data were taken from horses, dogs, squirrels, rats and mice.