A human powered wheelchair includes a frame, a seat mounted to the frame for supporting an operator having a torso, two independently driven wheels disposed at the rear of the wheelchair, and a JACKDRIVE™ propulsion system. The JACKDRIVE™ propulsion system includes two independent drive levers adapted to be grasped by the operator and to be pushed forward in a bench press movement away from the torso of the operator, a biasing member for exerting a biasing force to move each lever toward the torso of the operator, a driving chain connected to each lever, and a unidirectional driving mechanism operatively coupled to the driving chain and each driven wheel for directly translating the bench press movement of each lever into unidirectional motion of each driven wheel so as to propel the wheelchair in a forward direction.