title: Improving repeatability of setting volume origin and coordinate system for 3D gait analysis.
abstract: This study investigated the variability arising from replacement of different calibration objects. A new calibration object (L-Frame) was instigated which consisted of four markers screwed into fixed positions in the floor, to ensure consistency between replacements. The variability of a healthy subject's joint moments from replacement of different calibration objects (5 marker wand and L-Frame) was compared to the subject's stride-to-stride repeatability (SSR). Overall the L-Frame calibration object demonstrated the least amount of variation during object replacement for both sagittal and coronal joint moments. In particular for the coronal ankle moment the 5 marker wand positioned at the end of the force-plate alignment had a variability of 81% of SSR, while the L-Frame showed only 3% of SSR. Utilising the L-Frame to set the volume origin and global coordinate system achieved the most consistent results, which is important for assuring reliable measurements during 3-Dimensional Gait Analysis (3DGA).
authors.affiliation: Hugh Williamson Gait Analysis Laboratory, Royal Children's Hospital, Melbourne, Australia; Murdoch Childrens Research Institute, Melbourne, Australia. Electronic address: elyse.passmore@rch.org.au.
authors.forename: Elyse
authors.initials: E
authors.lastname: Passmore
authors.affiliation: Hugh Williamson Gait Analysis Laboratory, Royal Children's Hospital, Melbourne, Australia; Murdoch Childrens Research Institute, Melbourne, Australia; Department of Mechanical Engineering, University of Melbourne, Australia.
authors.forename: Morgan
authors.initials: M
authors.lastname: Sangeux
mesh_terms: D000843:Ankle Joint / Q000502:physiology; D001696:Biomechanical Phenomena; D002138:Calibration / Q000592:standards; D005684:Gait / Q000502:physiology*; D064368:Healthy Volunteers; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods / Q000592:standards*; D007596:Joints / Q000502:physiology*; D007719:Knee Joint / Q000502:physiology; D009068:Movement / Q000502:physiology*; D010808:Physical Examination; D015203:Reproducibility of Results
keywords: Calibration; Coordinate system; Joint moments