  We optimize the performance of an elastic actuator consisting of an active
core in a host which performs mechanical work on a load. The system, initially
with localized elastic energy in the active component, relaxes and distributes
energy to the rest of the system. Using the linearized Mooney-Rivlin
hyperelastic model in a cylindrical geometry and assuming the system to be
overdamped, we show that the value of the Young's modulus of the impedance
matching host which maximizes the energy transfer from the active component to
the load is the geometric mean of Young's moduli of the active component and
the elastic load. This is similar to the classic results for impedance matching
for maximizing the transmittance of light propagating through dielectric media.
