(a) Normalized swimming speed () (— —, left vertical axis) and the objective function (––, right vertical axis) as a function of Young's modulus (or equivalently bending stiffness for constant ).

The preferred curvature of a traveling wave is used to actuate the swimming motion. (b) Normalized swimming speed () (——, left vertical axis) and the objective function (––, right vertical axis) as a function of Young's modulus (or equivalently bending stiffness for constant ). The curvature at the optimal condition of (a) is used as the preferred curvature to actuate the swimming motion.