Abstract: An exercise machine is disclosed herein comprising: a frame; a lower crank mounted on the frame; a substantially identical upper crank mounted on the frame above the lower crank; a right moment arm pivotably connected to both upper and lower right crank arms; a left moment arm pivotably connected to both upper and lower left crank arms; a pedal pivotably connected to the bottom end of each of the moment arms; and right and left pedal connecting rods pivotably connected to right and left secondary crank arms, respectively, and to the right and left pedals, respectively. Simultaneous rotation of the lower crank in a forward direction and the upper crank in a reverse direction generates forward orbital motion of the pedals and flexion-type motion of the pedals, thereby simulating the movements of a user's feet during running and/or walking. The disclosed exercise machine may also provide for arm movements appropriate for running and/or walking.

Abstract: An exercise machine is disclosed herein comprising: a frame; a lower crank mounted on the frame; a substantially identical upper crank mounted on the frame above the lower crank; a right moment arm pivotably connected to both upper and lower right crank arms; a left moment arm pivotably connected to both upper and lower left crank arms; and a pedal connected to the bottom end of each of the moment arms. Simultaneous rotation of the lower crank in a forward direction and the upper crank in a reverse direction generates forward orbital motion of said right pedal and forward orbital motion of said left pedal, thereby simulating the movements of a user's feet during running and/or walking. The disclosed exercise machine may also provide for arm movements appropriate for running and/or walking.