An implantable lead has a lead body construction designed to accommodate loading forces exerted on the lead body during patient movement. The lead body may be sufficiently stretchable to resist forces that could otherwise cause lead failure, axial migration of the electrodes, anchor damage, or tissue damage. Increasing stretchability of a lead body can also increase the vulnerability of the lead body to flex fatigue, buckling fatigue, kinking, and crush. Therefore, the lead described herein includes conductors that comprise coiled wires positioned substantially parallel to a center axis of the lead. The conductors described herein may be coiled around fibers that limit the axial stiffness of the coiled wires to ensure full recovery from axial loading.