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    Hello Biomch-l subscribers,

    About 1 week ago I posted a request for information about using a
    new set of kinematic data with the GAITLAB software by Vaughan,
    Davis, and O'Connor. My project and problem was stated in a later
    response to those who replied to my original message:

    Hello Brian , Jeremy and Kit,

    Thanks a lot for the reply. I'd much rather talk to the source of
    the software than anyone else! Let me begin by describing my

    I am a mechanical engineer working on a project to develop a
    functional knee brace for athletes who have strained or ruptured
    their ACL. A common complaint about knee braces is that most of the
    force/strength testing done for them is either static or not
    representative of true athletic motions. Recently I performed some
    tests using an ARIEL motion analysis system to look at three motions:

    1 - A vertical jump landed on one foot
    2 - A cutting motion
    3 - A circular running motion(similar to turning the corner on
    a track)

    My goal was to enter the data into the GAITLAB package and see if it
    would give me results. I realized that the package is meant for GAIT
    analysis so I did not expect the animation segment to work.

    So far the program has accepted my COLIN.KIN file but when I try to
    run the "Center of Gravity" procedure using my COLIN.FPL file I get a
    "Run Time 200" error. As I see it my problems/differences with the
    software are the following:

    1 - Because the motions happen quite quickly, I only end up with
    about 40 frames worth using 1/60th s (0.0167) intervals

    2 - The data does not create a repetitive cycle like one would get
    from GAIT analysis

    3 - While my global reference frame and marker system are the same as
    the ones on page 23, I have only used 1 force plate to catch the
    heel strike

    Do you think that this use of GAITLAB is feasible?

    Thanks again,

    Colin Paranchych
    Department of Mechanical Engineering
    University of Alberta
    Edmonton, AB

    Here are the replies which I recieved:

    Dear Colin,

    In reply to your note :

    1. I'm not sure that the "Centre of Gravity" procedure uses the
    FPL file, but I'll get back to you on that.

    2. 40 frames shouldn't be a problem. The interval being 1/60'th of
    a second may be. I did adapt the program for private use by Kit
    Vaughan for 1/60'th time intervals but I think the software that was
    released to the public was 1/50'th of a second. I'll get back to you
    on that one as well.

    3. That you only have one force plate is probably going to cause
    problems, as I think the program expects 2 force plates in the .FPL
    file. One way (the easiest) to overcome this problem is to create a
    file with two force plates where the six values (per frame) for the
    second force plate remain zero for the 40 frames i.e. a dummy force

    4. As to whether the use of Gaitlab for your problem is feasible
    from a mechanics/mathematical point of view you should check with Kit
    Vaughan or Brian Davis. I don't see any problem from a software
    point of view - as long as the input data files you create have the
    correct format and content Gaitlab should handle the job.

    Jeremy O'Connor
    programmer, GaitLab Team.


    As I outlined in my prevoius message, Kit Vaughan does have a
    version of Gaitlab that uses three decimal places and accepts data at
    60 Hz. Perhaps he will be able to help you out.

    I'm pleased you managed to get the program working with your data.

    Jeremy O'Connor
    programmer, Gaitlab team.

    Dear Colin,

    Following up on your latest message and Jeremy's reply, there is
    a version of GaitLab that will run with 60Hz data. In the *.KIJN
    (that should be *.KIN) and *.FPL files, there must be 3 decimaol
    places for the time field, i.e. 0.017. You can get the
    executable files via anonymous ftp from in the
    public_access subdirectory. The file is called gaitlab.exe and
    it is a self-extracting ZIP file that creates GAITMATH.EXE and
    GAITPLOT.EXE files which will work with 60 Hz data. Let me know
    how it goes.



    I have not had the problem you have had because I 1) wrote a program
    which generates .kin files with the correct time interval, and 2) the
    new software (which I got from c. Vaughan; GAITMATH module is 100,544
    bytes) does not seem to have the problem you report. Let me know if
    you have the old or new software. I know I had lots of problems with
    the old which the new cleared up. All the best.

    Cheers ...

    Michael Raymond Pierrynowski, Ph.D.
    Human Movement Laboratory
    School of Occupational Therapy and Physiotherapy
    McMaster University, HSC 1J11
    Hamilton, Ontario L8N 3Z5

    1 905 525-9140 x22910 (PHONE)
    1 905 522-6095 (FAX)

    You might have less problem if you write your data with a program in
    C. There is somme incompatibilities with FORTRAN format.
    I use a FORTRAN program but i had to build the writting routine in C,
    so i was force to use a MIXED LANGUAGES program. I belive the format
    that the GAITLAB program is able to read is very restrictive.
    There is limit in the number of frame and if you tri to read more
    data the program crash.
    Universite de Montreal


    I have been using the GAITLAB software with the OPTOTRAK kinematic
    data acquisition system. We are currently looking at children with
    leukemia. After 25 subjects, with an average of 5 runs each I have
    found the GAITLAB software useful. Of course I had to write a bunch
    of linking software and I also wrote software to calculate powers,
    average across files and plot these results.

    I would be welcome to share my experiences with you.

    Michael Raymond Pierrynowski, Ph.D.
    Human Movement Laboratory
    School of Occupational Therapy and Physiotherapy
    McMaster University, HSC 1J11
    Hamilton, Ontario L8N 3Z5

    1 905 525-9140 x22910 (PHONE)
    1 905 522-6095 (FAX)

    I have a version of the Gaitlab software (Vaughan et al), but
    do not use it for any real data. My use is simply for class
    demonstrations, etc. (undergrad 'lab' work). There does seem
    to be a problem with timing of events, especially with the
    stick figures. For example, on page 69 of the accompanying
    text the toe-ons and toe offs for the stick figures do not
    line up with the LHS and RTO of the EMG diagrams below it.
    I have seen other similar timing problems, but am unable
    to come up with a specific example at this point. I have
    not contacted Human Kinetics about my observations. What
    problems have you experienced? Maybe with many inquiries
    to Human Kinetics we can get some explanations.
    Jeff Ives, PhD
    Dept. Exercise Science
    Campbell University
    Buies Creek, NC 27506


    Thanks again to all the replies, and especially to the authors of
    GAITLAB for clearing up my problem.

    Colin Paranchych
    University of Alberta
    Department of Mechanical Engineering