Influence of motor vehicle seat geometry on pelvic inclination

The purpose of the study was to investigate the influence of seat geometry and physical characteristics on pelvic inclination. Twenty-four males were studied in hard seat geometries representative of motor vehicle seating postures. A sonic digitizer was used to measure the inclination of the pelvis. The pelvis rotated 6$\sp\circ$ for every 11$\sp\circ$ increase in seat back angle from 108$\sp\circ$ to 130$\sp\circ$, and 1$\sp\circ$ for every 8 cm decrease in seat height from 31 cm to 15 cm. Minimal correlation was found between physical characteristics and pelvic inclination. The center of rotation (CR) of the pelvis was 12 cm in front of the seat reference point and 3 cm below the seat pan. A 2.5 cm rearward translation of CR was calculated by increasing seat back angle to 130$\sp\circ$. Subjects were measured in their preferred seat geometry. A method for estimating the location of pelvic landmarks was presented.