A computer-assisted medical system comprises a flexible elongate instrument. The flexible elongate instrument comprises a plurality of wires extending from a proximal end of the flexible elongate instrument to a distal end of the flexible elongate instrument. Each wire of the plurality of wires may be used to steer the distal end. The system also comprises a control system coupled to the flexible elongate instrument. The control system is configured to monitor movement of the flexible elongate instrument along a longitudinal central axis and determine an extent of motion of the flexible elongate instrument in a first direction along the longitudinal central axis based on the monitoring. The control system is also configured to alter a rigidity of the flexible elongate instrument based on a rigidity profile relative to the extent of motion by adjusting one or more forces applied by the plurality of wires to the distal end of the flexible elongate instrument.