The invention relates to a spring (1, 23) comprising at least one tensile body (2, 17, 71, 76) that can be subjected to tensile stress and/or at least one compressive body (37) that can be subjected to compressive stress, the spring also comprising a force-displacement conversion unit (3, 18, 24) for converting the force-displacement of the spring force F, said force-displacement conversion unit (3, 18, 24) having a moveable input control element (6, 19, 29), to which the spring force can be applied and a moveable output control element (7, 20, 30, 54, 60, 68, 72) which is operatively connected to the tensile body (2, 17, 71, 76) or to the compressive body (37) in such a way that the spring force F produces a tensile stress in the tensile body (2, 17, 71, 76) or a compressive stress in the compressive body (37) in a specific force-displacement conversion ratio.