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  • Re: trunk markers

    These are the responses to my previous e-mail:
    I am interested in measuring the amount of trunk "lean" in the
    sagittal plane during running. I would appreciate anyone's advice as to the best
    positions for the markers to describe the trunk segment.

    Thanks to all who responded!
    ************************************************** *********************
    .. ask to Moreno D'Amico , is the best expert in Italy
    ..
    Alberto Leardini, DPhil
    Movement Analysis Laboratory
    Centro di Ricerca Codivilla-Putti
    Istituti Ortopedici Rizzoli
    Via di Barbiano 1/10, 40136 Bologna ITALY
    tel: +39 051 6366522
    fax: +39 051 6366561
    email: leardini@ior.it
    http://www.ior.it/movlab/
    ************************************************** *********************
    Have a look on Syczewska's article, which was published on Clinical
    Biomechanics, v.14, p. 384-388, 1999. The group uses a number of markers
    placed along the spine to quantify spinal motions. Depending on the
    variables you want to quantify you may discard some of them...
    Best Regards

    Prof. Dr. Andre Luiz Felix Rodacki
    Departamento de Educacao Fisica
    Setor de Ciencias Biologicas
    Universidade Federal do Parana
    R. Coracao de Maria, 92 - BR 116, Km 95
    Jardim Botanico - Curitiba - Parana - Brasil
    Fone 262-7574
    FAX 362-3653
    E-mail: rodacki@ufpr.br
    ************************************************** *********************
    I pubished a paper in Clinical Biomechanics earlier this year (v18,
    655-661) in which we differentiated hip and trunk kinematics during various
    postural conditions. We used an electromagetic tracking system with senors
    placed on the C7 spinous process, the base of the sacrum, and mid-thigh.
    The trunk was defined by the sensors placed on C7 and the sacrum and the
    digitized hip joint center. Hip flexion was defined by the sacrum sensor,
    the digitized hip joint center, and the thigh sensor. I hope this helps.
    Good luck.

    Troy Blackburn, MS, ATC
    Doctoral Candidate in Human Movement Science
    University of North Carolina at Chapel Hill
    Sports Medicine Research Laboratory
    06-F Fetzer
    CB #8700
    Chapel Hill, NC 27599
    Phone: (919)962-7187
    Fax: (919)962-0489
    ************************************************** *********************
    To my knowledge, the Plug in Gait (PiG) upper body model has
    not been validated in any peer reviewed journal papers and therefore there are
    no articles on repeatability of the upper body model. Below are
    references to the PiG lower extremity model and then the full description of
    the PiG model (lower and upper). Let me know if the information below
    didn't transfer well via email.

    Sincerely,
    Nick


    Plug In Gait, Gait analysis software is based on the following journal papers:
    Bell, A.L., Pedersen, D.R. & Brand, R.A. (1990). A comparison of the accuracy of
    several hip center location prediction methods. Journal of Biomechanics, 23,
    617-621.Davis, R., Ounpuu, S., Tyburski, D. & Gage, J. (1991). A gait analysis
    data collection and reduction technique. Human Movement Sciences, 10, 575-
    587.Kadaba, M.P., Ramakrishnan, H.K. & Wooten, M.E. (1987). J.L. Stein, ed.
    Lower extremity joint moments and ground reaction torque in adult gait.
    Biomechanics of Normal and Prosthetic Gait. BED Vol (4)/DSC Vol 7. American
    Society of Mechanical Engineers. 87-92.Kadaba, M.P., Ramakrishnan, H.K.,
    Wootten, M.E, Gainey, J., Gorton, G. & Cochran, G.V.B (1989). Repeatability of
    kinematic, kinetics and electromyographic data in normal adult gait. Journal of
    Orthopaedic Research, 7, 849-860Kadaba, M.P., Ramakrishnan, H.K. & Wooten,
    M.E. (1990). Lower extremity kinematics during level walking. Journal of
    Orthopaedic Research, 8, 849-860.Macleod, A. And Morris, J.R.W. (1987).
    Investigation of inherent experimental noise in kinematic experiments using
    superficial markers. Biomechanics X-B, Human Kinetics Publishers, Inc.,
    Chicago, 1035-1039.Ramakrishnan, H.K., Wootten M.E & Kadaba, M.P. (1989). On
    the estimation of three dimensional joint angular motion in gait analysis. 35th
    annual Meeting, Orthopaedic Research Society, February 6-9, 1989, Las Vegas,
    Nevada.Ramakrishnan, H.K., Masiello G. & kadaba M.P. (1991). On the estimation
    of the three dimensional joint moments in gait. 1991 Biomechanics Symposium,
    ASME 1991, 120, 333-339.Sutherland, D.H. (1984). Gait Disorders in Childhood
    and Adolescence. Williams and Wilkins, Baltimore.Winter, D.A. (1990)
    Biomechanics and motor control of human movement. John Wiley & Sons,
    Inc.These references have information on kinematic and kinectic calculations, as
    well as anthropometrics and repeatability of the model.The upper body model
    has not been validated in any peer reviewed journal papers and therefore there
    are no articles on repeatability of the upper body model.
    ************************************************** *********************
    How are things going at UB? When i was at Penn State I looked at head and trunk
    kinematics during stair negotiation. I was more concerned about the upper trunk
    so my landmarks included C7, left and right acromion processes and the
    suprasternal notch. I used the marker cluster method (see pictures below) and
    digitized the anatomical landmarks with a calibration wand. Using this method
    you would need to subtract off the normal standing position because the vector
    from C7 to SSN will be pitched forward (this is only if you are looking at trunk
    angle in the global coordinate system). We ordered the plate that made up our
    trunk cluster from the Alimed catalog. You could use a lumbo-sacral marker
    instead of the SSN, but we weren't sure if that would stay stable relative to
    our cluster during movement. Let me know if you have any questions.

    Kate Hamel, PhD
    Assistant Professor in Residence
    Department of Physical Therapy and Rehab Science
    University of California San Francisco
    Box 0625
    San Francisco, CA 94143
    415-353-7695
    415-353-7221 FAX
    hamelk@ptrehab.ucsf.edu
    ************************************************** *********************
    How are you capturing your data? 3-D or 2-D? We have done some analyses
    here
    at NASA on this just to determine what kind of space requirements are
    necessary for a treadmill on ISS. We are happy to get the deviation of the
    trunk from the vertical, so we just use a marker on the shoulder top (where
    you would balance a parrot), and the hip.

    If you are interested in rotations, lean, and side to side motion, then you
    will need to create a 3-D reference frame attached to the trunk. Let mw know
    what you are thinking and I amy be able to help you more if you are still
    looking for help.

    John DeWitt
    Biomechanist
    NASA Johnson Space Center Exercise Physiology Laboratory
    ************************************************** *********************
    For model like Plug In Gait (Vicon) ther are four markers that define
    the trunk: Between the clavicles on the superior aspect of the sternum, at
    the xyphoid process at the inferior aspect of the sternum, at C7 and T10 on
    the back. Trunk lean is sagittal plane flexion with respect to the global
    xyz axis. Vicon calculates a spine angle that is the trunk segment relative
    to the pelvis (2 ASIS, 2 PSIS).

    Michael
    ************************************************** *********************
    It is not so simple to answer to Your question in the sense that it really
    does depend on the capabilities provided by the Movement Analysis system You
    use.
    In fact we developed a complete protocol and a very specialised signal
    processing algorithms in order to fully identify 3D spine morphology. This
    protocol and feature extraction algorithms have been proved to provide
    information and measurement comparable to X-Ray approach (both in the
    frontal and in the sagittal plane) when normal weight people are measured,
    while it should be managed with care when obese people are analysed
    especially in the sagittal plane measurement because fat thickness at rachis
    different levels could mask spine sagittal shape. The approach we developed
    to correctly identify 3D Spine shape is based on the measurements of at
    least 13 markers positioned on the following body landmarks:
    11 on the spine starting from C7 to S3 every second vertebra
    2 on the Posterior Superior Iliac Spine
    The 2 markers on the PSIS allow to establish a subject linked co-ordinate
    system to frame by frame correctly identify the frontal, sagittal and
    horizontal subjetc's referred planes.
    The 11 markers on the rachis should be considered as the necessary minimum
    marker set to correctly identify 3D spine shape at a comparable level with
    X-Ray information. In fact we proved no signal processing procedure can
    provide reliable results for Spine clinical parameters extraction such as
    Kyphosis Lordosis angles and Spine sagittal lean amount in relationship with
    its shape, by using a smaller set of markers.
    This is because to obtain such shape information signal smoothing and
    derivatives assessment are necessary and this is a very difficult task when
    very few noisy data point are to be processed i.e. at least 11.
    We presented in the past a special automatic signal processing Smoothing and
    Derivatives assessment procedure named LAMBDA[1,2,3] we compared with
    the
    best published on literature obtaining very good outcomes (...superior) on
    biomechanical data to obtain velocities accelerations and even jerks
    estimation from noisy markers trajectories. Indeed we needed to further
    improve such signal processing algorithm [3] to obtain reliable shape
    results from the 11 markers on spine.

    To answer to Your question it firstly should be established what kind of
    information You want to obtain. If in fact You only need some sagittal
    spinal offset measurements (i.e. horizontal displacements with respect to
    vertical line of some vertebra) a good solution could be to place a marker
    on S3 vertebra determine the vertical line passing through S3 and then to
    compute the horizontal distances with respect to this line. Added good
    points in this case are the C7 vertebra and the apexes of thoracic Kyphosis
    and Lumbar Lordosis, these latter two positions are different per each
    subject and should be detected and marked by clinical inspection.
    If You need more detailed information on Spine shape, so You need to use the
    above described minimal set of 13 markers for trunk posture and pose. Of
    course other markers have to be considered to detect legs movement during
    running so this will be a high demanding task for the Motion analyser You
    use. In particular a crucial step is for sure the tracking and labelling
    one, when 13 Spine and pelvis markers are included in the model.
    In our experience we had full 3D information on spine during walking but we
    did not approach running yet. If Your opto-electronic system is able to
    measure and correctly track the minimum 13 marker set or better a set of 27
    markers or higher and obtain the measurements collected on a C3D file, give
    me a feedback and we could agree a suitable protocol. In such a case in fact
    Spine or a full skeleton model could be identified and You could send me a
    C3D file of a running trial You acquire and I'll send You back what it is
    possible to extract with our processing approach.
    I've attached some of our publications [3,4,5,6] on the argument to provide
    You some more details.

    I hope this is something helpful to You.
    Best regards


    Dr. Ing. MORENO D'AMICO
    BIOENGINEERING & BIOMEDICINE COMPANY S.R.L.
    Sede Legale Via C.D. Spiga 10
    65124 Pescara
    Sede Operativa Via Aterno 154 (giĆ  Via Salara 7)
    66020 San Giovanni Teatino (CH)
    C.F. - P. IVA 01457770681
    Tel. (+39) 085-4463940
    Fax: (+39) 085-4408450

    [1] M. D'Amico and G. Ferrigno, Technique for the Evaluation of Derivatives
    from Noisy Biomechanical Displacement Data Using a Model-Based
    Bandwidth-Selection Procedure, Med. & Biol. Eng. & Comput. 28, 407-415,
    1990.
    [2] M. D'Amico and G. Ferrigno, Comparison between the More Recent
    Techniques for Smoothing and Derivative Assessment in Biomechanics, Med. &
    Biol. Eng. & Comput. 30, 193-204, 1992.
    [3] M. D'Amico and P. Roncoletta, "A new self-adapted digital filtering
    procedure for data smoothing and differentiation ", Proceedings of the XVIII
    ISB (Inetrnational Society of Biomechanics) Congress, Zurich (Switzerland),
    8-13 July 2001.
    [4] M. D'Amico, G. D'Amico and P. Roncoletta, A 3-D Parametric Biomechanical
    Skeleton Model for Posture and Spine Shape Analysis. In Research into Spinal
    Deformities 3 (eds. A. Taguy and B. Peuchot) IOS Press 2002 Proc. Of 3rd
    Congress of International Research Society of Spinal Deformities,
    Clermont-Ferrand (France) 26-29 May 2000, pp365-369.
    [5] M. D'Amico and P. Roncoletta: Baropodographic meaurements and averaging
    in Locomotion and postural analysis. In Research into Spinal Deformities 4
    (ed. T. B. Grivas) IOS Press 2002 Proc. Of 4 th Congress of International
    Research Society of Spinal Deformities, 24-27 May 2002 Athens Greece, pp.
    156-161.
    [6] M. D'Amico and P. Roncoletta: Joint Segmental Kinematic Trunk Motion and
    C.O.P. Patterns For Multifactorial Posturographic Ananlysis. In Research
    into Spinal Deformities 4 (ed. T. B. Grivas) IOS Press 2002 Proc. Of 4 th
    Congress of International Research Society of Spinal Deformities, 24-27 May
    2002 Athens Greece, pp. 149-152.
    ************************************************** *********************
    What kind of system are you using? Most of my experience is with VICON.
    Would
    the
    positions we've used be of any help to you?

    I'm a working on my Master's in Biomechanics and just started working for a
    MoCap
    manufacturer in Canada. Our system might be usefull for you, as it isn't
    limited by
    outside cameras, electromagnetic fields or hardwiring.

    If that sounds interesting, please drop me a line.

    john

    john brown
    Special Projects Directror
    Measurand
    john@measurand.com

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