Flat cushion vs Shaped cushion: comparison in terms of pressure distribution and postural perceived discomfort

Abstract

A proper seat is crucial not only for preventing health issues but also for the (dis)comfort perception. In the design of a seat, the seat pan’s geometric shape, either in or under the cushion, plays a vital role as it constrains the deformation of the foam it supports. The contact area and pressure distributions between the foam and the human body, closely associated with (dis)comfort, are influenced by those constrained deformations. In this paper, using a comparative study, the aim is to determine if opportunely shaped seat pans are better than a standard flat pan regarding postural comfort and pressure distribution. Two cushions with the same type of foam but two different seat pans were used in the comparison. The first seat pan is the standard one used in current aircraft seats and the second is a shaped seat pan, which was designed following the mean buttock-thigh shape of an international population (including P5 females and P95 males). Twenty-two international participants (11 males and 11 females, with BMI between 16 and 30) took part in the blind experiment. Results indicated that the cushion with shaped seat pan performed better as it led to less postural comfort, a larger contact area and more uniform pressure distribution. Also, 64% of participants favored the cushion with the shaped seat pan as they felt it was more comfortable and suitable for the buttock shape.