An implantable lead has a lead body construction designed to accommodate loading forces exerted on the lead body during patient movement. The lead body is sufficiently stretchable to resist forces that could otherwise cause lead failure, axial migration of the electrodes, anchor damage, or tissue damage. The lead body may include a variety of features that reduce the axial stiffness of the lead without significantly impacting the operation and structural integrity of lead components, such as electrodes, conductors and insulators.