Abstract: An elliptical system is disclosed having a crank assembly configured to be adjusted in length to accommodate users having varying gaits. In some embodiments, the crank assembly includes a crank and an axle connection bracket that is slidably adjustable with respect to the crank. For example, the crank assembly can include a crank link having a longitudinal body, where the longitudinal body is connected to the crank at one end and includes a longitudinal slot slidably coupled with the axle connection bracket. The axle connection bracket is configured to slide through a plurality of positions along the longitudinal body. In some embodiments, the crank assembly further includes a screw for adjusting the axle connection bracket with respect to the crank, where the screw can cause the axle connection bracket to slide through one or more positions of the plurality of positions when the screw is turned.

Abstract: A gait replication apparatus can include a scalable mechanical mechanism configured to replicate different gaits. The scalable mechanical mechanism can include, for example, a four-bar linkage, a pantograph, a cam/Scotch-yoke mechanism, and so forth. In some embodiments, the mechanical mechanism includes a beam rotating about an axis passing proximate to its center, with a foot pedal slidably coupled with the beam, and a timing chain/belt or cable pulley-pair coupled with the foot pedal and looped about the beam. A method can include decomposing a foot path defined by Cartesian coordinates into polar coordinates, and providing a mechanical support for a foot, where a first mechanism controls an angular position of the mechanical support with respect to a reference frame, and a second mechanism controls a radial distance of the mechanical support from the reference frame.

Abstract: An elliptical system is disclosed having a crank assembly configured to be adjusted in length to accommodate users having varying gaits. In some embodiments, the crank assembly includes a crank and an axle connection bracket that is slidably adjustable with respect to the crank. For example, the crank assembly can include a crank link having a longitudinal body, where the longitudinal body is connected to the crank at one end and includes a longitudinal slot slidably coupled with the axle connection bracket. The axle connection bracket is configured to slide through a plurality of positions along the longitudinal body. In some embodiments, the crank assembly further includes a screw for adjusting the axle connection bracket with respect to the crank, where the screw can cause the axle connection bracket to slide through one or more positions of the plurality of positions when the screw is turned.