Summary: Custom upper extremity marker sets
We have been using Vicon's MX system with Nexus software to study the ergonomics of surgeons performing laparoscopic surgery. We used Vicon's Plug-in-gait (PIG) model for the kinematic calculations. We are interested in evaluating wrist and hand movements. Previously we encountered problems with the PIG model because the wrist extension and flexion angles seemed to be "flipping" between the X and Y graphs depending on what position the forearm was in (e.g. Having the palm of the hand pointing upward vs. downward). The upper limb model seems to address that problem, however we are searching for more sophisticated upper extremity models. Is anyone conducting movement analysis on tasks that involve a great deal of forearm rotation? If yes, what market set and model are you using to best calculate the wrist angles? Are there any modified PIG or custom-designed models that exist that better capture the wrist angles? Thank you.
Using model developing software like Visual 3D or Motion Monitor to calculate joint angles from the c3d files is a better option because it allows you to manipulate the angle sequence. Changing the angle sequence may also help eliminate issues related to gimbal lock. Gimbal lock may occur when you loose a degree of freedom because two of the axis become parallel. In this situation the movement can only occur in two dimensions. Avoid this problem by adjusting the angle sequence according to the movement task so that the axis with the greatest angles is first in the sequence.
Suggested models included:
Upper Extremity (UE) model from San Diego (however it was developed for baseball)
Model described by International Society of Biomechanics
Model described in Ergonomics (Brown, J. N. A., Albert,W. J., & Croll, J. (2007). A new input device: Comparison to three commercially available mouses. Ergonomics, 50, 208-227.)
Model described by Metcalf et al. (2008), Validation and application of a computational model for wrist and hand movements using surface markers. IEEE Transactions on Biomedical Engineering. Vol 55 issue 3.
NIOSH developed a 6DOF model of the hand and fingers, and presented its kinematic and kinetic performance at GCMAS and ASB this year.
Another model for dart and hammer throwing motions was developed at The University of Texas Medical Branch.
Suggestions for building a custom model
Model which uses a 6 degree of freedom approach
Use cluster marker sets: You may place a cluster on the proximal forearm, distal forearm and/or hand.
Marker placement on the olecranon to define the forearm vector (olecranon is better option than lateral epicondyle because it is located on the ulna as opposed to the humerus)
Marker placement on the 3rd metacarpal base and head of hand (to track the orientation of the hand)
Discretion has been used since some custom marker models have not been published.
Magnetic tracking was also suggested because there is no line-of-sight required, can be worn underneath clothing and tracks with in full 6DOF.
Martin Warner MSc BSc
Faculty of Health Sciences
University of Southampton
Division of Biomechanics and Bone Physiology Research
Department of Orthopaedic Surgery and Rehabilitation
The University of Texas Medical Branch
Human Performance Laboratory
University of Calgary
Matthew B. A. McCullough
Department of Chemical, Biological and Bioengineering
North Carolina A&T State University
Albert Einstein Hospital
Arnel Aguinaldo, MA, ATC
Director, Center for Human Performance
Motion Analysis Laboratory
Rady Childrens Hospital
Frank L Buczek Jr, PhD
Branch Chief, HELD/ECTB
Coordinator, MSD Cross Sector Program
National Institute for Occupational
Safety and Health (NIOSH)
Research and Technology Applications
Human Performance Lab
Department of Physical Therapy
University of New England
Andrew Kraszewski, MS
PhD Candidate, Ergonomics and Biomechanics, New York University
Leon Root, MD Motion Analysis Laboratory
Hospital for Special Surgery
Tameka A. Clanton, MS, ATC
Department of Surgery/MASTRI
University of Maryland Medical Center
22 South Greene Street
Baltimore, MD 21201-1593
(410) 328-8432 (office)