Abstract
The purpose of this study is to evaluate the subject handling tasks from the viewpoint of biomechanic during the wheelchair transfer helped by a physical therapist (PT) and a student. The center of gravity (CG), the angles of the hip and the knee and the mechanical works for the whole body of the two helpers, the one was a trained PT and the another was a student, were calculated. The movement distance of the CG, the changes of the joint angles and the works were compared between the PT and the student. The motions of the two helpers were videotaped with three video cameras operating at 30 Hz. Three-dimensional coordinates for determining the mechanical work were computed by using Direct Linear Transformation Method from video data. The CG of the student moved about 11% longer distance than the PT during carrying the subject from the bed to wheelchair. The preceding result explains that for PT, because the operating time of subject handling was shorter and moving distance of the CG was smaller, the load acting on the PT was smaller. But on the other hand, the mechanical work of the PT had greater changes than the student, because of the greater keen joint extension of PT. In the lifting movements, to avoid lower back disorder, the PT extended mainly her knee joints to left the subject instead of using the extension of her hip joint. This kind of movement may cost some more energy but will be safer to the low-back of patient handler.
