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The Real Dempster - Thankyou

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  • The Real Dempster - Thankyou

    Yesterday I asked about some inconsistencies in the reporting of Dempster's
    anthropometric data (full query below). Thanks to Pascale Pigeon, Jim
    Patton, DI Miller (himself!), and D Gordon E Robertson for supplying the
    following references:

    Miller D and Nelson R (1973) Biomechanics of Sport: A Research Approach, Lea
    and
    Febiger, Philadelphia.

    Plagenhoef S, Evans FG, Abdelnour T (1983) Anatomical Data for Analyzing
    Human
    Motion, Research Quarterly for Exercise and Sport, Vol 54, No 2, pp 169-178.

    Plagenhoef S (1971) Patterns of Human Motion: A Cinematographic Analysis,
    Prentice-Hall, Inc., Englewood Cliffs, New Jersey.



    Gordon also supplied the following explanation and two web-site references
    which will be interestingly to anyone working in this field. I reproduce his
    comments in full:


    When you add up the proportions that Dempster and Plagenhoef report the
    total body does not add up to 100%. This was attributed mostly due to fluid
    and flesh losses during the dissections of the cadavers. Miller and Nelson
    report values where they redistributed the missing mass proportionally
    throughout
    the body parts to the totals add up to 100%. Plagenhoef also added some
    proportions for dividing the trunk into several parts etc. I recently went
    through
    all four sources (Dempster, Plagenhoef, Miller & Nelson and Winter) to
    obtain
    a comprehensive list of the proportions. You can find them plus the various
    equations at:
    http://www.health.uottawa.ca/biomech/csb/ARCHIVES/dempster.pdf

    You can also view a similar table for the proportions developed by Clauser
    et al. and Chandler et al. It is found at:
    http://www.health.uottawa.ca/biomech/csb/ARCHIVES/clauser.pdf
    Clauser (and Chandler) used bony landmarks instead of joint centres of
    rotation
    as their segment end points so don't expect the "r" and "k" values to be the
    same. Definitions of their landmarks are provided with the table.

    These data are contained in the Canadian Society for Biomechanics website
    at:
    http://www.health.uottawa.ca/biomech/csb/



    Thanks to all of you and also to all you guy's keeping Biomch-L up and
    running. It's a great system!

    Richard


    Original question:

    I'm reviewing Dempster's 1955 data on the position of the centre of mass of
    different body segments. I've got a copy of the original report which
    appears to contain a couple of typographical errors (e.g. position of CM of
    lower leg with and without foot is identical). Winter (Biomechanics of Human
    Movement, John Wiley, 1979 p151) cites Dempster but gives different values
    which look more convincing (0.433 from knee without foot, 0.606 with).
    Winter cites the data as having come "via Miller and Nelson" or "via
    Plangenhoef".

    Does anyone out there have an explanation for this or know a reference for
    either Miller and Nelson or Plangenhoef?

    Richard Baker PhD
    Gait Analysis Service Manager
    Musgrave Park Hospital, Stockman's Lane, Belfast, Northern Ireland, BT9 7JB
    Tel: +44 2890 669501 ext 2155 or 2849
    Fax: +44 2890 382008

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