Implements, particularly medical instruments, formed at least in part of elongated polymer members, exhibit high torque fidelity after processing with tension, heat, and twisting. The processing orients the polymer in generally helical paths so that torque imposed at the proximal end can be transmitted to the distal end without substantial whipping, even if the implement follows a long and tortuous pathway. Applications include medical guidewires, catheters, and driveshafts.