Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1997.Includes bibliographical references (leaves 64-65).A pressure management and relief system has been developed for use by wheelchairbound individuals who are at risk of developing pressure sores. This system can be used in passive or active form, depending on an individual's requirement for pressure management and relief. The active seat uses vacuum and pressure in combination with an open-cell-foam-based cushion to perform pressure relief. Testing methods for the system were studied and developed. These methods allow a controlled and precise testing of seating systems. Prototype systems have also been produced and tested. Experimental equipment and data are presented to support performance claims. Prototypes of both active and passive systems have also been tested in a pilot clinical study to assess their effectiveness. Results from this study are presented.by Gustavo Y. Buhacoff.S.M