The invention relates to a sternal support for a hyperextension frame which includes a mounting (2) combined with a front plate (7), and damping elements (9) that maintain a separation distance between the mounting (2) and the front plate (7). The mounting (2) and the front plate (7) are joined together via attachment devices (8) which include central portions accommodated inside coaxial holes (9a) of the damping elements (9)； wherein the front plate (7) can be adjusted in three spatial directions substantially perpendicular to one another. The sternal support can be adjusted in three spatial directions, substantially improving the adaptation thereof to the body of the patient, thus minimising impacts and allowing adjustment in terms of its elastic amplitude as well as its adaptability to irregular areas of the patient's body.
