Hi,
I was wondering if it would be possible to find the contributions of various things (muscles, gravity, inertial forces, etc.) to knee joint loading with a model that has contact spheres on the foot. I have the muscle's mtu force, excitation and joint kinematics from the simulations that I performed within SCONE, but I am having trouble implementing these datasets to OpenSim to find the muscle contributions. I was planning on using JointReaction, but I found out that JointReaction does not display contribution results. Any advice or alternative methods are appreciated.
Thank you,
Eric Hu
Contributions to Joint Loading with Contact Geometries
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Jon Stingel
- Posts: 35
- Joined: Fri Jan 19, 2018 5:54 pm
Re: Contributions to Joint Loading with Contact Geometries
Hi Eric,
Perhaps one option that you can consider is to set up multiple versions of the joint reaction analysis? In this case, each version of the analysis has only the muscles and components that you want to see the contributions from. The analysis itself is fairly computationally inexpensive, so you can run multiple versions for each of your motion trials, and then compare the forces. For example, this might look like 1) no muscles in the model providing just intersegmental forces, 2) quadriceps in the model providing intersegmental and quads contributions, etc.
Hope this helps!
Jon
Perhaps one option that you can consider is to set up multiple versions of the joint reaction analysis? In this case, each version of the analysis has only the muscles and components that you want to see the contributions from. The analysis itself is fairly computationally inexpensive, so you can run multiple versions for each of your motion trials, and then compare the forces. For example, this might look like 1) no muscles in the model providing just intersegmental forces, 2) quadriceps in the model providing intersegmental and quads contributions, etc.
Hope this helps!
Jon
Re: Contributions to Joint Loading with Contact Geometries
Hi Jon,
Thank you so much for this consideration. I tried disabling each muscles and running JointReaction multiple times to find the contributions of that muscle to the joint reaction force. However, I came to a realization that the ground contact model (Hunt-Crossley Model) and the prescribed motion that I have inputted will produce the same motion and GRFs regardless of which muscle I disable. My next step was to try and run IAA to find the muscle contributions to the GRF and accelerations, but I was not able to get the same GRFs with a rolling constraint. Can you tell me if this reasoning is correct or not and if I should proceed to run IAA for the GRF and acceleration decomposition?
Thank you,
Eric
Thank you so much for this consideration. I tried disabling each muscles and running JointReaction multiple times to find the contributions of that muscle to the joint reaction force. However, I came to a realization that the ground contact model (Hunt-Crossley Model) and the prescribed motion that I have inputted will produce the same motion and GRFs regardless of which muscle I disable. My next step was to try and run IAA to find the muscle contributions to the GRF and accelerations, but I was not able to get the same GRFs with a rolling constraint. Can you tell me if this reasoning is correct or not and if I should proceed to run IAA for the GRF and acceleration decomposition?
Thank you,
Eric
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Edward Syrett
- Posts: 40
- Joined: Mon Jan 14, 2019 11:04 am
Re: Contributions to Joint Loading with Contact Geometries
Hi Eric,
I have also had trouble running IAA with the rolling constraint. The output does not seem right, and it seems to me that the constraints are not being properly enforced. I wish I had other information to offer, but wanted to let you know you're not alone in that difficulty.
Dan
I have also had trouble running IAA with the rolling constraint. The output does not seem right, and it seems to me that the constraints are not being properly enforced. I wish I had other information to offer, but wanted to let you know you're not alone in that difficulty.
Dan