thorax spine

Hey,
i’m using Anybody version AMMR.v.1.5.1 and i’m working with the GaitFullBody model. I used it as basis for some modifications. Now I would like to know how i can implent a more detailed thorax spine. At the moment I have only flexible element is the cervical and in the lumbar spine but the thorax spine is one stiff element. How can i change that? I’m analysing kicks (Taekwondo) and therefore i done need a high ROM in the spine…

Best Regards,
Johannes

Hi Johannes,

As you correctly mentioned the thorax is a single undeformable piece right now - the primary reason and an assumption that the thorax motion is low in everyday life as compared to the lumbar and cervical regions. There is no way to just switch it on at this point. To make it move you would really need to disassemble the thorax into segments, introduce joints between them, move muscle attachment nodes. Some users have worked on this issue and you could try searching and contacting them. For example, Gregor Spreiter from ETH Zurich has presented his work at CMBBE 2012, named: Influence of kyphosis on spinal loading.

You could also implement it yourself looking at the lumbar region implementation. And if you let us know what your research question is - we may help with some suggestions how to do that or what can be done instead of implementing it.

Best regards,
Pavel

Hi Pavel,
thanks for your quick reply. I captured kinematic and kinetic data during differents sports. For example as I said Taekwondo. We used a Vicon system + kistler force platforms. The goal of my research is to find out the loading (force/moments) between different segments of the spine.

I would be happy to get some suggestions from you.

I already got some joint moments from the lumbar spine (just from the selected output file). All results are given in SI-convention, right? I’m asking because jointmoments seem a bit less (about factor 10) compared to earlier research…

Another question: Is there a way to get the rotation angle between the segments, I can only find the joints position.

Thanks for your help and have a nice weekend!
Jo

Hi Johannes,

Because Pavel will be out of office for several weeks from now so I’m trying to make an reply for you instead.

  1. All the units for forces and moments in the AnyBody Modeling System are based on the MKS unit system.

  2. If you think that the result of your model is strange then I would recommend you to upload your model in the debug section.
    http://forum.anyscript.org/forumdisplay.php?f=21

  3. You can define an AnyKinRotational object between two AnyRefFrame objects. Please see the detail description of this class in the reference manual.

Best regards,
Moonki

P.S) Long time ago, I also tried to test the Taekwondo motion by myself. :slight_smile:
https://www.youtube.com/watch?v=d4AkNbw33AQ

Hey Moonki,
I watched the sequence on youtube, looks very nice. I gonna upload the model including the cd3-file in the other folder. I would be realy happy if you couls have a look at it!

Best regards
Jo