Abstract: The present invention is a drive mechanism for human powered vehicles. In general, the invention is a unique drive mechanism for any human powered vehicle, such as a bicycle or a human powered boat. The mechanism enables the operator to efficiently apply both arm and leg power for motive force while maintaining the ability to steer using the arms. The mechanism couples the arm and leg motion in a harmonious union similar to a running motion but can be easily uncoupled should the operator prefer to power the vehicle only with leg power. The mechanism enables motive power to be applied with both the up and down stroke of either or both arms. Specifically the drive mechanism has oscillatable handlebars and a linkage connectable to the drive of the human powered vehicle.