Measuring of pressure forces in sitting.

We were able to re-examine already known facts in tests of pressure areas in seats by using a new analytic system. It was shown that only in backrest seat angles of 90 and 110 degrees pressure areas below the ischial tuberosities were clearly defined. The transition area of zones of high to medium pressure was sharply defined with these angles. In the anterior position and with large backrest seat angles high pressures were not found and the transition areas between zones of medium and low pressure became fluent. Only the pressure distribution pattern in the 90 and 110 degrees position is physiologic and corresponds to the pressure tolerance of different parts of the human body in seats. This pattern has to be maintained principally in a contoured and upholstered seat.