Theo Jansen built wind-powered walking mechanisms or strandbeasts using a basic 12-linked leg mechanism which has a single degree of freedom (DoF). In this work, the Jansen leg mechanism is used as a start point in an optimization routine to arrive at a single DoF mechanism to trace the ankle trajectory. Optimization and forward dynamic analysis methodology of the mechanism are presented. This preliminary work can be used in the design of rehabilitation devices and assistive exoskeletons. © 2021, Springer Nature Singapore Pte Ltd.