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    Dear Subscribers,

    I couple of months ago I posted a question about the Hammer throw. Below
    is a copy of the original email as well as the responses that I
    received. Many thanks to all who replied.
    Sara Jaycock
    AIS Biomechanics
    Post-Graduate Scholar
    Phone: +61 2 6214 7898
    Mobile: 0421 188 555

    Dear Subscribers,

    I'm carrying out a study on hammer throwing and have obtained many
    articles about the kinematics of the throw, and whilst some of these
    papers have derived applied forces, there does not appear to be much in
    the way of kinetic analysis. The forces derived from kinematic data
    depend upon the models used and it is doubtful how well these models
    represent the actual movement. I am interested in the development of the
    force applied to the hammer prior to release, the impulse produced and
    the time between maximum force developed and release.

    If anyone has any suggestions or information I would greatly appreciate
    your response.

    __________________________________________________ ______________________

    There is no research regarding the kinematics of the hammer throw. We
    attempted mounting multiple force plates in the ring this past fall.
    USOC Olympic training center has the capablity to mount them this way.
    We were unable to acquire data due to software problems. We are hoping
    to attempt again this summer.

    The problem I foresee is the length of the movement, direction of the
    movement, time of movement, and rotational motions. The direction is
    not linear across the ring making it hard to place force plates. The
    length and the time of movement are long in terms of collecting data off
    forces plates.

    In my opinion, maximum force will occur at the transition into turn 1
    due to increased friction and inertia on the system, especially in male
    throwers. As the athlete increases velocity in the turns the force they
    are able to apply is lessening.
    Even the block after return to DS would probably not have as much force
    due to momentum of the system.

    The studies done by Dapena are the best kinematic data you will find.
    The deriving of applied forces based upon this information will be as
    accurate as the calibration. My suggestion would be to utilize that
    approach. Or, the use of accelerometers or strain gauges attached to
    the athlete or mounted within the ball. This may prove to be costly
    however due to the units being possible broken with every throw.

    I hope something I have written is of help to you.

    Suzie Konz, MS ATC CSCS
    Doctoral Student
    Brigham Young University
    Physical Education Department
    __________________________________________________ ______________________

    I don't know how much help it will be to you, but I recommend that you
    check some of the past issues of the Soviet sports Review (Table of
    Contents is available at and in some libraries.

    the Russians did extensive research on the hammer throw and much of it
    is available in Russian. The only English sources that I know of are in
    the above journal.

    Michael Yessis, Ph.D
    President, Sports Training, Inc.
    __________________________________________________ ______________________

    Here's an article with some references you might look into, though it
    looks like there's just not much out there:

    Try to look in the Russian literature, though it's tough
    because a lot of it is untranslated.

    Also, check out this guy:

    Jesus Depena

    Here's a link to one of his publications:

    Alexander "Sandy" Chase
    __________________________________________________ ______________________

    If the kinematic data for the hammer is accurate, then it is a simple
    matter to derive the forces between the hammer and the human body. The
    hammer is with good approximation a particle, so you only have to
    differentiate the positional vectors twice and multiply them by the mass
    of the hammer.

    However, differentiating twice will increase the error in the positional
    data by two orders of magnitude, so the kinematic data must be really
    good or at least subjected to a reliable filtering.

    I cannot resist mentioning that if you have the kinematics of the hammer
    AND the athlete then you can perform an inverse dynamics simulation of
    the forces using the kind of technology we develop in our project, i.e.
    the AnyBody Modeling System. Please refer to for more information or write to me personally if
    you have specific questions about this.


    John Rasmussen,
    Associate Prof., PhD, The AnyBody Group, Institute of Mech. Eng. Aalborg

    __________________________________________________ ______________________

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