A planetary gear system in an exercise machine featuring a flywheel; an axle shaft positioned through the center of the flywheel, a sun gear disposed on the axle shaft and fixedly attached to the flywheel, a housing disposed on the axle shaft, a planet carrier fixedly attached to the axle shaft and disposed in the housing, and a ring gear fixedly attached in the housing. One or more planet gear wheels are rotatably attached to the planet carrier. The planet gear wheels can rotate independently of the planet carrier. Rotation of the axle shaft in a first direction rotates the planet carrier in the first direction, thereby causing the planet gear wheel to rotate in a second direction within the ring gear. Rotation of the planet gear wheel in the second direction causes the sun gear and the flywheel to together rotate in the first direction.