The influence of wheelchair cushions and deflection of the wheelchair seat on sitting motion

Abstract

Purpose : The purpose of this study was to investigate quantitatively how wheelchair cushions and the deflection of the wheelchair seat influence sitting motion. Methods : Head, trunk and pelvic movements from side to side on a wheelchair were measured in nine healthy males and females using a Vicon motor analysis system. Sitting motion was measured under ten conditions: four wheelchair cushions and no cushion (with or without a board on the seat for each measurement). Outcomes were movement distance from center of gravity and the pelvic angle on the frontal plane. Results : A Roho one-valve cushion had significantly less movement distance from the center of gravity than a J2 cushion or no cushion. No cushion and the Roho one-valve cushion resulted in significantly smaller pelvic angles than the J2 and Varilite cushions. There were no significant differences with or without a board for movement distance and pelvic angle. Conclusions: Material and structure of seating faces influenced movement distance from the center of gravity on the frontal plane. Shaped cushions that supported the great trochanter resulted in a greater pelvic angle on the frontal plane. The deflection of the wheelchair seat had no influence on either outcome.