A medical system includes a medical instrument and first and second manipulators. The medical instrument includes a tendon that extends from an interface at a proximal portion of the medical instrument to an actuated element at a distal portion of the medical instrument. The first manipulator is configured to actively engage the tendon at a first location on the tendon to provide a preload tension. The second manipulator is configured to actively engage the tendon at a second location on the tendon to actuate the actuated element. One of the first manipulator or the second manipulator is configured to pull the tendon along a longitudinal axis of the tendon and the other of the first manipulator or the second manipulator is configured to deflect the tendon laterally with respect to the longitudinal axis.