Methods and devices are provided for rotating an end effector on a long, flexible medical device. The methods and devices utilize an actuator mechanism that is effective to rotate an end effector on the distal end of an elongate flexible shaft. The actuator mechanism is movable between a freely rotatable position and a rotationally resistant position. When the actuator mechanism is in a freely rotatable position, the actuator mechanism can be rotated to impart torque to the end effector, and thus at least a distal portion of the elongate shaft, to cause the end effector to rotate. In order to prevent the actuator mechanism from "freewheeling," wherein the actuator mechanism freely rotates in an opposite direction upon release rather than the end effector rotating in the desired direction, the actuator mechanism can be moved to the rotationally resistant position.