Although many different kinematic structures have been employed in the design of elliptical machines for exercise and fitness, these devices in general do not produce pedal paths that promote lower extremity kinematics similar to overground gait. This is unfortunate given the growing interest in using these devices as a gait rehabilitation tool. In this paper, we present a novel design strategy for elliptical machines intended to create a movement profile that more closely simulates the lower extremity kinematics of gait. This involves replacement of the typical crank link with a modified Cardan gear system. Simulations of typical rear-drive (crank-rocker) and front-drive (crank-slider) elliptical designs validate the improvement in lower limb hip and knee kinematics using this approach, suggesting that assistive elliptical rehabilitation systems can be more optimally designed to promote normal lower extremity gait kinematics compared to currently available devices.