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Fig. 1. A diagram of the model for muscle-powered accelerations at rest (A) and
during a contraction (B). To simulate a muscleleverload system
(inset) with an effective mechanical advantage that could vary during the
contraction, the muscletendon unit operated across a gearing system
that included a controllable gearbox to accelerate a load. The muscle
consisted of several actuators acting in parallel to produce muscle
forcevelocity, lengthtension and activation properties. The
movement was subject to inertial and gravitational forces. The properties and
dimensions of the muscle and the load were chosen to approximate the entire
hindlimb and body of a jumping frog.