Abstract: The dynamic support (1) comprises means (3) for the cyclic inflation and deflation of an air chamber (2). The air chamber (2) is divided into two half-chambers (2A) having a common rigid laminar element (4) to be positioned on a seat back. When the half-chambers (2A) are inflated they press mainly against the muscular tissue of the lumbar region of the user's back, with the exception of his vertebrae and ribs.

Abstract: A chair, comprising a chair seat which automatically and continuously swings in such a way as to change the position of the body of the seated person. As compared with the known chairs, the chair of the present invention has the advantage of breaking or interrupting the body immobility and the rigidity of muscles. The regular and continuous swinging movement of the chair seat induces the back to move and the muscles of the vertebral column to work. Circulatory activity is thus enhanced and the consciousness of the vertebral column is increased in the seated position of the body.