a machine body including a first support structure which has front and rear ends, and a second support structure which extends upwardly from said first support structure;

left and right cranks mounted rotatably to said first support structure on two opposite sides of an imaginary vertical plane which extends in a front-to-rear direction;

a swing unit including left and right rotary shafts which are mounted rotatably to two opposite sides of said second support structure on the opposite sides of the imaginary vertical plane, and left and right handles, each of which has an intermediate part mounted to a respective one of said left and right rotary shafts; and

left and right pedal rods, each of which is connected to a respective one of said left and right handles and a respective one of said left and right cranks, said left and right pedal rods respectively having left and right foot plates thereon,

said left foot plate being movable along a left elliptical path that has a forward portion extending to a right side of the imaginary vertical plane and a rear portion extending at a left side of the imaginary vertical plane,

said right foot plate being movable along a right elliptical path that has a forward portion extending to the left side of the imaginary vertical plane, and a rear portion extending at the right side of the imaginary vertical plane.