“…The relationship between pressure and soft tissue injury has led many to encourage the use of overlays, mattresses, and therapy beds to prevent pressure ulcers (Bristow, Goldfarb, & Green, 1987;Daechsel & Conine, 1985;Doughty, Fairchild, & Stogis, 1990;Parish & Witkowkski, 1980;Stoneberg, Pitcock, & Myton, 1986). Interface pressure, the pressure between the skin and the support surface, is the criterion clinicians and manufacturers use most often to assess these products.…”