title: Mechanical testing for three-dimensional motion analysis reliability.
abstract: The purpose of this study was to use simple mechanical tests to evaluate the reliability of three-dimensional motion analysis systems and biomechanical models. Three different tests were conducted at four motion analysis laboratories where clinical care and research studies are routinely performed. The laboratories had different motion capture systems, different types and number of cameras, different types and numbers of force plates and different biomechanical models. These mechanical tests evaluated the accuracy of the motion capture system, the integration of the force plate and the motion capture system, and the strength of the biomechanical model used to calculate rotational kinematics. Results of motion capture system accuracy tests showed that, for all labs, the error between the measured and calculated distances between markers was less than 2mm and 1° for marker separations which ranged from 24mm to 500mm. Results from the force plate integration tests demonstrated errors in center of pressure calculation of less than 4mm across all labs, despite varied force plate and motion system configurations. Finally, errors across labs for single joint rotations and for combined rotations at the hip and knee were less than 2° at the hip and less than 10° at the knee. These results demonstrate that system accuracy and reliability can be obtained allowing the collection of comparable data across different motion analysis laboratories with varying configurations and equipment. This testing is particularly important when multi-center studies are planned in order to assure data consistency across labs.
authors: Motion Analysis Laboratory, Mayo Clinic, Rochester, MN, United States.
authors: Emily
authors: E
authors: Miller
authors: Biomechanics-Motion Analysis Laboratory, Mayo Clinic, Charlton North L-110L, 200 First Street SW, Rochester, MN, United States. Electronic address: kaufman.kenton@mayo.edu.
authors: Kenton
authors: K
authors: Kaufman
authors: Naval Medical Center San Diego, CA, United States.
authors: Trevor
authors: T
authors: Kingsbury
authors: Walter Reed National Military Medical Center, Bethesda, MD, United States.
authors: Erik
authors: E
authors: Wolf
authors: Center for the Intrepid, Brooke Army Medical Center, JBSA Fort Sam Houston, TX, United States.
authors: Jason
authors: J
authors: Wilken
authors: Naval Medical Center San Diego, CA, United States.
authors: Marilynn
authors: M
authors: Wyatt
mesh_terms: D001696:Biomechanical Phenomena; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D009038:Motion; D015203:Reproducibility of Results
keywords: Gait; Motion analysis; Motion capture system validation; Reliability