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Anthropometry for Paraplegics

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  • Anthropometry for Paraplegics

    Thank you very much to all those who replied to the request I posted (twice
    somehow) for help with estimating anthropometric parameters for paraplegics.

    While I am grateful for the assistance, I don't think we've got to the heart of
    the question yet. I wish to be able to calculate parameters for a subjects who
    clearly do not fit normative tables. Surely the same problem has been
    approached by every researcher who has performed kinetic analyses. How do
    people studying the kinetics of weightlifting derive these parameters? The
    standard tables must be nearly bad for these people as they would be for
    paraplegics. We need a method to CALCULATE values for any given population. The
    geometric methods described below will assist, but they cannot provide the
    whole solution. I would welcome a reply from people from people doing all kinds
    of kinetic research to know how they get parameters for any non-standard

    Thank you once again to all those who replied before. I have included all your
    responses below.


    Peter Sinclair
    The University of Sydney

    From: SMTP%"IVMEMOL@HDETUD2.TUDELFT.NL" 27-JAN-1993 18:56:05.01

    Maybe I can help tomorrow; together with Douglas Hobson I analyzed
    anthropometric data from 122 people with cerebral palsy. He brought
    the dataset with him from Memphis Tennessee when he vistited our
    lab for his sabattical.

    We used regression equations of Clauser, CE, JT McConville and JW Young
    Weight, volume and center of mass of segments of human body
    Wright-Patterson Air Force Base Ohio(1969) AMRL-TR-69-70
    for example Center of Mass of Tibia:
    0.309 * tibial height - 0.558 * knee breadth +5,786 cm
    The data about the CP-sample is published as:
    Hobson, DA and JFM Molenbroek
    Anthropometry and Design for the disabled: Experiences with seating
    design for cerebral palsy population
    Applied Ergonomics 21(1990)1,43-54
    With regards
    Johan FM Molenbroek
    Delft University of Technology
    The Netherlands

    From: SMTP%"GA4020@SIUCVMB.SIU.EDU" 28-JAN-1993 02:20:32.14

    -although not directly designed for paraplegics, you might use part of
    the Hanavan body model to predict the location of segmental mass
    centers. The input data are radii of the distal and proximal ends of
    the segment and the segment weight (which of course you have to derive
    from some other means). The output will also include the moment of
    inertia around the mass center.
    The reference is: Hanavan, E.P. (1964) A mathematical model of the
    human body. AMRL Technical Documentary Report 64-102, Wright-Patterson
    Air Force Base.

    -The hanavan body model is a set of equations that predict the moment of
    inertia and location of the center of mass of the frustum of a right
    circular cone (the base of the cone with the tip cut off). The basic
    assumption of the model is that the segment has a constant density
    throughout the length of the segment. The application of this model to
    a human body segment also assumes the segment to be shaped like the
    frustum of a cone. Namely, for any of the extremity segments, the wider
    proximal end is the base of the cone and the narrower distal end is the
    top of the cone.
    -The input parameters to the model are: segment length, segment weight,
    segment mass, radius of proximal end, and radius of distal end.
    We obtain these values from:
    segment length - position data of segment in space
    segment mass - we use the values from Dempster predicting each segment
    mass from total body mass
    segment weight - mass * accel of gravity
    radii - we measure the proximal and distal circumferences of each
    on each subject and calculate radii.
    -The equations are as follows. The variable names come directly from
    hanavan. R is the proximal radius, RR the distal radius (R > RR).
    SL, SM, SW are segment length, mass, and weight.
    Eta is location of mass center expressed as a ratio of the length from
    proximal end to mass center and the segment length (eg Eta = .5 is mass
    center at mid point, Eta < .5 is mass center closer to proximal end).
    Seg In is the moment of inertia in SI units.
    Delta = (3 * SW) / (SL * (R^2 + R * RR + RR^2) * 3.14159)
    Mu = RR / R
    Sigma = 1 + Mu + Mu^2
    Eta = (1 + 2 * Mu + 3 * Mu^2) / (4 * Sigma)
    Aa = (9 / (20 * 3.14159)) * ((1 + Mu^2 + Mu^3 + Mu^4) / Sigma^2)
    Bb = (3 / 80) * ((1 +4 * Mu + 10 * Mu^2 + 4 * Mu ^3 + Mu^4) /
    Seg In = (Aa * SM^2) / (Delta * SL) + (Bb * SM * SL^2)
    Here is some test data for you to check the equations:
    Total body mass = 83.4
    SL = 0.353
    SM = 8.34 ( this was a sub's thigh = 0.10 * body mass)
    SW = 81.8154
    R = 0.1003
    RR = 0.0653
    Delta = 10614.2246
    Mu = 0.6508
    Sigma = 2.0743
    Eta = 0.4305 (notice how similar to other predictions of CM location)
    Aa = 0.0625
    Bb = 0.0795
    Seg In = 0.0837 (a very reasonable number)
    Good luck with this, Peter. If you have trouble let me know.

    Paul DeVita

    From: SMTP%"GA4020@SIUCVMB.SIU.EDU" 30-JAN-1993 03:17:16.44

    From: SMTP%"" 28-JAN-1993 05:51:50.48

    I am doing some research work in structural and functional anthropometry
    of wheelchair mobile paraplegics. I attempted to perform some
    work using the methods decribed by Jensen (1979), J. of Biomechanics.
    However, I found it difficult to get subjects to volunteer for the
    slides necessary for his method. Please keep me posted of your


    John Kozey
    ps I am using the account of Nancy Black for this letter. Please respond
    to her account.

    From: SMTP%"" 28-JAN-1993 09:10:21.51

    Our laboratory is also currently facing the problem of getting
    good anthropometrical estimates of paraplegics and paraparetics.
    We are working presently on using Hatze's equations even
    though the density of the segments will have errors.
    We would appreciate it very much if you could send us the replies
    you will get with your query so that we could improve our kinetic

    Thank you for your time.

    Michel Ladouceur, M.Sc.
    Human Gait Laboratory
    School of P. & O. T.
    McGill University
    Montreal, Canada
    e-mail: michel@physocc.lan.mcgill.can

    From: SMTP%"" 28-JAN-1993 21:11:09.93

    I had intended to post a similar call for help, but know I am lazy enough
    to ask you to summarize the answers you get and either post them on BIOMCH-L
    or send them to me.

    We are working on FES for paraplegics and need the data to feed our dynamical
    simulation program.

    Thank you for your kind help


    Rene Steiner

    Neurologisches Therapiecentrum
    Hohensandweg 37
    D-4000 Duesseldorf 13

    From: SMTP%"" 2-FEB-1993 04:05:21.83

    I wonder why you want to do this? There is some school of thought that
    anthropometrics is not everything it has been cracked up to be! It
    certainly helps in defining the range of values for design purposes
    but is dangerous if you expect to design for the "average" person. I
    find it interesting to think in terms of an "average para's" legs.
    Of what use would it be considering that the legs are non-functional?

    I think you might be hard pressed to find the data you are looking for
    considering how different every para is....even more so than able-bodied

    Good luck!..

    Jerry Weisman
    Vermont Rehab Engineering Center
    University of Vermont

    From: SMTP%"" 4-FEB-1993 01:59:59.57

    All anthropometric variables you want: mass, location of mass
    centre can be foud in Winter DA, Biomechanics of human movement,
    John Willey&Sons, New York 1979.
    I modelled shank and thigh as truncated cone with bigger
    and smaller radius. This is not published yet, but:
    from body mass and hight and according to Winter body density,
    segment densities and segment masses are determined. From mass and
    density segment volume can be found. You can also express mass
    location in terms of r1 and r2 of cone. And you can express volume
    in terms of r1 and r2. Both nonlinear equations include two radius
    r1 and r2 and can be solved with appropriate numeric method
    (Newton-Raphson). Works.
    I don't have experience with CT scans, but for body density
    non CT scan measurements would only count.

    With best regards,

    Marko Munih

    Marko Munih, M. Sc. Faculty of El. & Comp. Eng.
    Teaching Assistant Trzaska 25, 61000 Ljubljana, Slovenia tel.: +386 1 265 161
    fax.: +386 1 264 990