Forces in the Knee Joint Whilst Rising from Normal and Motorized Chairs

Knee joint forces were determined by kinesiological techniques using a high speed camera and force platforms so that a comparison could be made for rising from a normal chair without the aid of arms and with the aid of a motorized chair. For rising from a normal chair, the knee joint forces parallel to the long axis of the tibia at the point of contact between the tibia and femur, were found to be up to seven times body weight at about the time when the body left contact with the chair. Using a motorized chair the knee joint forces were reduced to less than body weight until normal standing was achieved.