What is interface pressure?

The term interface pressure (IP) is used widely in the area of wheelchair seating to describe the physical interaction between the buttocks and the seat surface. Methods of quantifying IP exist even though a formal, research-based definition does not exist. Using a previously proposed definition of IP, issues surrounding the definition are examined relative to research studies to show weaknesses in the definition. Additional concerns relative to current methods of quantifying IF, such as creep and hysteresis, are evaluated. Two alternative methods of considering the seating interface are presented. One involves standardization of IP measurement via an index whereas the other discards IP in favor of quantifying tissue deformation. It is concluded that a new method of considering the seating interface is required which allows for comparison between measurements and individuals.