title: Comparison of hierarchical and six degrees-of-freedom marker sets in analyzing gait kinematics.
abstract: The objective of this study was to determine how marker spacing, noise, and joint translations affect joint angle calculations using both a hierarchical and a six degrees-of-freedom (6DoF) marker set. A simple two-segment model demonstrates that a hierarchical marker set produces biased joint rotation estimates when sagittal joint translations occur whereas a 6DoF marker set mitigates these bias errors with precision improving with increased marker spacing. These effects were evident in gait simulations where the 6DoF marker set was shown to be more accurate at tracking axial rotation angles at the hip, knee, and ankle.
authors: a Department of Biomedical Engineering , University of Wisconsin-Madison , Madison , WI , USA.
authors: Anne
authors: A
authors: Schmitz
authors: b Shriners Hospitals for Children® , Erie , PA , USA.|c OMM and MSK Research, Lake Erie College of Osteopathic Medicine (LECOM) , 1858 West Grandview Blvd, Erie , PA , 16509 , USA.
authors: Frank L
authors: FL
authors: Buczek
authors: b Shriners Hospitals for Children® , Erie , PA , USA.
authors: Dustin
authors: D
authors: Bruening
authors: d Department of Physical Medicine and Rehabilitation , Harvard Medical School , Cambridge , MA , USA.
authors: Michael J
authors: MJ
authors: Rainbow
authors: b Shriners Hospitals for Children® , Erie , PA , USA.
authors: Kevin
authors: K
authors: Cooney
authors: a Department of Biomedical Engineering , University of Wisconsin-Madison , Madison , WI , USA.|e Department of Mechanical Engineering , University of Wisconsin-Madison , Madison , WI , USA.|f Department of Orthopedics and Rehabilitation , University of Wisconsin-Madison , Madison , WI , USA.
authors: Darryl
authors: D
authors: Thelen
mesh_terms: D001696:Biomechanical Phenomena; D003198:Computer Simulation; D057918:Fiducial Markers; D005684:Gait / Q000502:physiology*; D006801:Humans; D007596:Joints / Q000502:physiology; D008954:Models, Biological
keywords: forward dynamics; hierarchical marker set; inverse kinematics; marker clusters