Abstract: An exercise machine having a force transmission assembly rotatable in first and second directions, first and second wheels rotatable in first and second directions, a first directional coupler that couples the force transmission assembly to the first wheel when the force transmission assembly rotates in the first direction, and a second directional coupler that couples the force transmission assembly to the second wheel when the force transmission assembly rotates in the second direction. The first directional coupler allows the force transmission assembly to rotate with respect to the first wheel when the force transmission assembly moves in the second direction, and the second directional coupler allows the force transmission assembly to rotate with respect to the second wheel when the force transmission assembly moves in the first direction. A resistance mechanism may be configured to resist rotation of the first and second wheels independently from each other.