Converting Schutte1993 to Millard2012

[Ivan Alpatov]

Hi!

1) I want to use Upper Extremity Dynamic model available at SimTK for my research. This model uses Schutte1993Muscle_Deprecated and I wanted to replace it with more modern model like Thelen2003 or Millard2012. So I wanted to ask, if there are any simple means to do that and do metabolic probes behave correctly with old muscle model? I've searched the forum and have found some topics related to this problem, but there wasn't any straightforward answer.

2) Another problem is that I'm using IMUs in my experiments, but they are not Xsens'. And I really wanted to use OpenSense to be able to calibrate model and use Inverse Kinematics Tool but OpenSense require other format of data(Xsens or APDM) than I have from my IMUs. So another question is: can I somehow run Scaling and IK Tool without having .trc or Xsens or APDM types of files?

[Michael Asmussen]

Hi Ivan,

With respect to your first question, have you tried opening your model up in something like Notepad++ and then replacing the Schutte1993 muscle with the Thelen2003 or Millard2012 muscle?

Also, maybe just field your second question in another topic because it is a different issue.

I hope this helps!

Mike

[Ivan Alpatov]

Hi Michael,

Yes, I've opened .osim files in VSCode many times to compare different models and muscle models in particular. According to reply on one of the forum's similar topics replacing old model of muscle isn't just changing the type of the muscle in .osim file. As I've understood from investigation of different .osim files Schutte1993 muscle model has some parameters that are not present in Millard2012 and vice versa but I'd be very happy if you'll point out my mistakes.
Moreover when I tried to compare Millard2012 and Thelen2003 implementations of the same muscle I discovered that even parameters that are the same in both models have different values in these models. So I don't know where to obtain muscle parameters' values from. I also couldn't find any model of upper extremity with Millard type of muscle so if you know any such model it'd be great if you'll give a reference to it in this topic.

Best,

Ivan

[Michael Asmussen]

Hi Ivan,

Have you tried this upper arm model: https://simtk.org/projects/thoracoscapular

Also, what is your intended use of an upper arm model? Have you implemented the Millard muscle model and ran into some issues when using the model?

All the best,

Mike

[Ivan Alpatov]

Hi Michael,

Thank you very much for giving a reference to https://simtk.org/projects/thoracoscapular model! I don't know why it wasn't on the search results when I searched for upper extremity models. I'd want to use this model for my research on influence of upper limb passive exoskeleton on efficiency of overhead work.
I couldn't implement Millard or Thelen muscle models because of the reasons I've written in my previous post.
I think it'd be important to notice that the model https://simtk.org/projects/thoracoscapular failed to open in OpenSim with error "Attempting to assign invalid SimTK:MobilizedBodyIndex" but then I enabled the plugin ScapulothoracicJointPlugin40 and finally the model has opened.

Thank you very much again for your help!

Best,

Ivan

[Michael Asmussen]

Hi Ivan,

Do you need any more help with the Thelen or Millard muscle model or does the new model suit your needs?

All the best,

Mike

[Ivan Alpatov]

Hi Michael,

Yeah, the model's pretty good, the only thing I'm worrying about is where from I can get ratio_slow_twitch_fibers for muscles in the model. I've found these ratios only for lower limb muscles. The thing is that without these ratios metabolic probes don't work as they should. So maybe you have some information about it? It'd be very nice if that would be the case.

Best,

Ivan

[Michael Asmussen]

Hi Ivan,

I don't have many references for slow versus fast twitch muscles in the upper arm muscles. I think you have to dive into the literature and see what you can find. Here is one reference that might be helpful for some upper body/upper arm muscles "Data on the Distribution of Fibre Types in Thirty-Six Human Muscles. An Autopsy Study ".

Alternatively, you can maybe use a parametric analysis for the fast twitch fibre ratio that you do not know and see how much that influences your results.

I hope this is helpful!

Mike