A method of forming a stimulation lead includes forming an implantable lead body, including helically winding at least one cable about a mandrel to form a coiled cable assembly in a first, restrained state. Helically winding the at least one cable includes applying a tensile force to the at least one cable as the at least one cable is wound about the mandrel. Forming the lead body also includes releasing the tensile force from the at least one cable to allow the coiled cable assembly to release stored mechanical energy and transition from the restrained state to a second, relaxed state in which the coiled cable assembly is substantially free of stored mechanical energy. The method further includes subjecting the lead body to a reflow process by applying heat to the lead body, where the tensile force is released prior to the lead body being subjected to the reflow process.