Hip joint centre location from anatomical landmarks for automotive seated posture reconstruction

38ième congrès de la Société de Biomécanique francophone, MARSEILLE, FRANCE, 06-/09/2013 - 09/09/2013; Measuring hip joint centre (HJC) for seated posture in an automotive environment is a difficult task, because only a very limited number of anatomical landmarks (ALs) can be measured. There exist two classes of methods for estimating HJC location (see Bull et al. 2012 for a short review): regression method and functional method. However, they are not well suited to be directly applied to automotive seated posture. Recently, Bull et al. (2012) showed that the uncertainty in HJC by these two methods applied to automotive seated posture could be up to 4 cm due to errors in AL manual palpation and soft tissue artefacts. Interestingly, Bush and Gutowski (2003) proposed a method of locating HJCs for seated postures only using the right and left anterior superior iliac spines ([R/L]IAS) and the right or left femoral lateral epicondyles of the knee by assuming that the distances between HJC and these three ALs remained constant when changing posture. These distances needed to be firstly determined in an initial reference posture by Seidel's method. However, one strong limitation of Seidel's method is that the palpation of the pubic joint landmark (IPJ) is required, which usually causes volunteers to feel uncomfortable. Similar to the method by Bush and Gutowski, the aim of this study was to explore other ALs than IPJ for determining HJC. More specifically, the ilium ischial tuberosity (IIT) could be an alternative candidate as it can be indirectly estimated with the help of a pressure map by assuming that the highest pressure point corresponds to IIT when seated on a flat hard surface. In this study, data collected by Universite ?Libre de Bruxelles (ULB) from 48 adult cadaveric specimens were used for establishing regression equations. The proposed equations were compared with other existing bony landmark-based methods