Hello!
For my project I would really like to be able to extract knee valgus angles from the downloadable opencap data! I was wondering where that info is stored, if it all?
I was kind of thinking it could be knee_angle_beta, but after further inspection I am not sure! What is Knee_angle_beta referring to?
Secondly,
how does your program calculate knee valgus?
Thanks for the continued help!!
Sydney
knee valgus calculation
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Antoine Falisse
- Posts: 428
- Joined: Wed Jan 07, 2015 2:21 am
Re: knee valgus calculation
Hey Sydney,
The model we use has a single degree of freedom at the knee joint. If you would like to get knee valgus angles, you should use a different musculoskeletal model and reprocess your data locally.
- Here is the repository of opencap-core: https://github.com/stanfordnmbl/opencap-core
- Here is a script you can use to reprocess your data locally: https://github.com/stanfordnmbl/opencap ... essions.py
- Here is where the OpenSim part is done: https://github.com/stanfordnmbl/opencap ... in.py#L381
- Here is where the opensim models live: https://github.com/stanfordnmbl/opencap ... ine/Models
In brief, what you could do is use this code but point to your own musculoskeletal model with the extra degrees of freedom at the knee.
Let us know for questions, we are happy to provide support,
FYI, knee_angle_beta is related to the patella, not to the valgus angle.
Best,
Antoine
The model we use has a single degree of freedom at the knee joint. If you would like to get knee valgus angles, you should use a different musculoskeletal model and reprocess your data locally.
- Here is the repository of opencap-core: https://github.com/stanfordnmbl/opencap-core
- Here is a script you can use to reprocess your data locally: https://github.com/stanfordnmbl/opencap ... essions.py
- Here is where the OpenSim part is done: https://github.com/stanfordnmbl/opencap ... in.py#L381
- Here is where the opensim models live: https://github.com/stanfordnmbl/opencap ... ine/Models
In brief, what you could do is use this code but point to your own musculoskeletal model with the extra degrees of freedom at the knee.
Let us know for questions, we are happy to provide support,
FYI, knee_angle_beta is related to the patella, not to the valgus angle.
Best,
Antoine
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Sydney Barta
- Posts: 5
- Joined: Mon Jun 26, 2023 2:23 pm
Re: knee valgus calculation
Hi!
Thank you for the help!
I have just a few more questions. What about the patella is the knee_angle_beta measuring?
And secondly, what is the difference between lumbar bending and lumbar extenstion; it seems to me that these measurements would be the same movement but just positive or negative.
Thank you!
Sydney
Thank you for the help!
I have just a few more questions. What about the patella is the knee_angle_beta measuring?
And secondly, what is the difference between lumbar bending and lumbar extenstion; it seems to me that these measurements would be the same movement but just positive or negative.
Thank you!
Sydney
-
Antoine Falisse
- Posts: 428
- Joined: Wed Jan 07, 2015 2:21 am
Re: knee valgus calculation
The patella is a body in the model, and there is a joint linking it to the femur; knee_angle_<>_beta is the name of the coordinate of that joint. Take a look at the model here: https://github.com/stanfordnmbl/opencap ... h2022.osim
You can visual the difference between both coordinates using the OpenSim GUI. Extension is in the sagittal plane, bending in the frontal plane.
You can visual the difference between both coordinates using the OpenSim GUI. Extension is in the sagittal plane, bending in the frontal plane.