View Full Version : Re: SUMMARTNormal gait: Are joint angle standard deviationslarger atma ximal joint angular velocities?

Dr. Chris Kirtley
04-16-2003, 05:01 AM
Dear Arturo and others,

I think this warrants a bit more discussion. The SDs are clearly smaller
during periods of HIGH angular velocity in all the plots I have looked
at - and the effect is most pronounced in the knee angle. Compare the
stance and swing flexion peaks (when velocity is zero) with the rising
and falling parts of swing phase flexion (when velocity is relatively
high) in this data from a MAC system in Vienna:

Other data on the CGA normative data page e.g.:

Vienna (MAC system): http://www.univie.ac.at/cga/data/kinematics.jpg
Belfast (Vicon): http://www.univie.ac.at/cga/data/Baker/anon.jpg
Dundee (Vicon): http://www.univie.ac.at/cga/data/Linskell/linskell.jpg

shows the same general trend, although the Vicon data is not quite so

So I think there must definitely be a methodological reason why yours
and the Dutch follow the opposite pattern. This is very interesting, and
I as I say I think we ought to get to the bottom of it!

Dr. Chris Kirtley MD PhD
Associate Professor
Dept. of Biomedical Engineering
Catholic University of America
620 Michigan Ave NE, Washington, DC 20064
Tel. 202-319-6134, fax 202-319-4287
Email: kirtley@cua.edu

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