Methods

In this study, an alternative technical pelvic coordinate system to the standard right and left anterior superior iliac spine (ASIS) and posterior superior iliac spine (PSIS) is developed and evaluated in two healthy male subjects (slim and overweight). The alternative system consists of a cluster of 3 retro-reflective markers attached to the Sacrum, thus allowing position and motion of the pelvis to be measured. In order to use these technical markers a static trial must be performed. The ASISs were calibrated relative to the technical frame; and the anatomical frame of the pelvis was defined relative to the technical coordinate frame. Each participant completed 5 walking trials and the angular rotations of the two methods were investigated using Euler angles.