Research on pelvic angle variation when using a pelvic support.

A pelvic support consisting of a forward sloping wedge of foam has been tested as an addition to conventional office seating for VDT work. In experiment 1 a questionnaire investigation was carried out on the impressions of 10 male and 10 female subjects who sat using pelvic supports. A general result from the questionnaire was that the waist and pelvis were felt to be stable and the evaluation was more positive with the support than without. In experiment 2, pelvis and chest inclinations were measured during sitting with and without the pelvic support. Over a long work period, significant differences were not observed. In both cases, subjects were able to move freely and there were no significant changes in posture. In experiment 3, pelvis and chest inclinations were measured in conditions of no pelvic support and with supports of 10, 20 and 30 degrees. The experiment demonstrated that a support angle of 10 degrees was stable and comfortable. In this research, it was found that the change of inclination of the pelvis can be measured continuously using an angle of inclination sensor. Imposing a forward slope of 4 to 10 degrees on the seat pan surface using the pelvic support had a positive effect, while angles of 20 and 30 degrees had a negative effect.