. An exercise-aid device comprising:
a transmission mechanism comprising a motor, a first shaft, and a second shaft, said first shaft and said second shaft being rotatably supported by said base, said motor including an output shaft rotatably supported by said base, a worm being provided on said output shaft, a drive gear being mounted on said first shaft to turn therewith, said drive gear meshing with said worm, a follower gear being fixed to a side of said drive gear to turn therewith, said follower gear being mounted on said first shaft, a driven gear being mounted on said second shaft to turn therewith, said driven gear meshing with said follower gear; and
a pair of cranks each having a pedal mounted thereto, each said crank being securely attached to an end of said second shaft to turn therewith;
said worm and said drive gear providing a first-stage reduction, said follower gear and said driven gear providing a second-stage reduction, thereby providing a torque sufficiently high for driving said pedals to turn.