2017 Volume 53 Issue Supplement2 Pages S730-S731
The aim of this study was to investigate the effects of driving posture changed by seat condition including seat heights (high, low), seat angles (94, 109 degree), and either with or without lumbar support in separated seat on lumbar flexion moments. Recent trends in auto industry has led the higher vehicle seat comfort, which is one of the most important factors in selecting a car. However, the biomechanical aspect of driving posture while seating on a seat have received less attention. Even though researchers have suggested an ideal posture for drivers to reduce load on L5/S1, there has been no equipment found for measuring lumbar flexion moment in real time as driving posture changes. All 25 participants (between the ages of 27 and 46, 73.5 ± 11.5 kg, 1.74 ± 0.11 m) should have never suffered from musculoskeletal disorders and any kind of orthopedic surgery around the lumbar region. The separated seat is consisted of two parts including seat pan and seat back and the seat pan was connected to the force plates. All participants took a seat on the seat, which was adjusted for seat back angle (94/109 degree according to ground) and height (Top/ Mid.) with lumbar support (presence/absence) in order to induce various driving postures. Reaction forces were collected with force plates (Advanced Mechanical Technologies, Inc., Newton, MA, USA) and the data of marker position were collected by using an eight-infrared-camera and three-dimensional motion analysis system. (Vicon, Oxford Metrics LTD, Oxford, England) The data of L5 location was changed by car seat condition. Seat back reaction force results showed a significant difference in seat back angle with absence lumbar support. (P=0.0215, P=0.0208) Lumbar flexion moments results showed that there was significant difference in seat back. (P=0.0433, P=0.0005, P=0.0159, P=0.0227) There was no significant difference in seat height and lumbar support. These results indicate that the seat back angle may be the main cause of decreased driver’s lumbar flexion moment. However, other car seat adjustment factors for lumbar flexion moment does not have any significance (P>0.05) This study suggested that lumbar flexion moment may be a new method of measuring seat comfort. Further study should be conducted to find out the relationship between spine curve and lumbar flexion moments.
