Fig. 3. Measured and predicted relationships of relative stride length (RSL) to body mass (M_b) in horses trotting at a Froude number of 0.5. Crosses are measured values, solid line is allometric equation fitted to measured values , broken line is relationship predicted with linear tendon properties , circles are relationship predicted with realistic nonlinear tendon properties . The predicted effect of size is substantially reduced by taking into account the nonlinear properties of tendon, but is still greater than measured experimentally. This suggests that additional factors compensate for size effects in horses.