Marker by VICON and EMG

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fady alnajjar
Posts: 10
Joined: Wed Mar 02, 2011 2:19 am

Marker by VICON and EMG

Post by fady alnajjar » Wed Jun 29, 2011 8:41 pm

Dear All,

I have a marker data of a subject walking on treadmill using VICON. I also having some of the muscle EMG data.
I want to import these data to opensim. One target is to compare between muscle activation calculated by opensim, and the resulted actual EMG data. And Also I would like to see if I can add both marker data and EMG data to opensim to calculate other muscle activations.

One problem I have is that Marker by VICON is scaled in 60Hz, while the EMG data scaled by 1000Hz. what shall I do? Any suggestion?

Also, Do you know any paper that do compare between actual EMG data, and muscle activation calculated by opensim?



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Marika B
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Joined: Wed Jul 25, 2012 6:09 am

Re: Marker by VICON and EMG

Post by Marika B » Mon Nov 05, 2012 9:14 am

I would also like to do something similar to what fadyalnajjar was doing. Was any solution found?

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Ayman Habib
Posts: 2235
Joined: Fri Apr 01, 2005 12:24 pm

Re: Marker by VICON and EMG

Post by Ayman Habib » Mon Nov 05, 2012 12:59 pm

Hi Marika,

There are multiple tools on the simtk.org website to process Vicon motion data, in particular https://simtk.org/home/lee-son and a set of Matlab scripts to do the same from c3D files if you can output those on other projects https://simtk.org/project/xml/downloads ... oup_id=660 and https://simtk.org/home/c3dtoolbox

Please try these and let us know how it goes. You typically use marker data only to solve InverseKinematics, while simulation/analysis results are computed at a higher frequency/sampling rate. How you normalize EMG and compare it to activations is a more involved question that you'll need to address then.

Best of luck,
-Ayman

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