Marker error for each marker, and max knee range.

[Ana Azevedo]

Hi all,

We are using OpenSim 3.3 to analyze single-leg jump-landing tasks. We exported markers trajectories from V3D, and converted into trc files.

1) After scaling and running inverse kinematics, the maximum marker error and RMS are reported. However, we would like to know how to get the marker error for each marker that we have and not only the maximum error and RMS. How can we obtain that information?

2) A second question is that some of our subjects have more than 10 degrees of hyperextension in the static pose, and the xml file has a maximum knee range set as 10 degrees (see attached image please). The question is should we change the maximum knee range to 20 degrees? And if so, will that have any impact on the results of the knee or other joint angles? Or it is preferable to leave the max value as 10 degrees?

Thank you in advance,
Ana

Static pose Opensim Forum.docx

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[jimmy d]

This forum post may help;
viewtopicPhpbb.php?f=91&t=4355&p=10342& ... _locations

The question is should we change the maximum knee range to 20 degrees? And if so, will that have any impact on the results of the knee or other joint angles? Or it is preferable to leave the max value as 10 degrees?

You should make modeling decisions that help you answer your research question. If your subjects have a degree of freedom that is greater than that set in the model, you should try to capture that. Be aware of what ramifications modeling decisions may have. You may find this paper useful;
http://nmbl.stanford.edu/publications/pdf/Hicks2015.pdf

[Ana Azevedo]

Thank you for your help,
Ana