I have a question regarding the output of the inverse dynamics study. I need to report the net external moment (or equivalently, the net internal muscle moment) for the lumbar joints. However, I can only find this value for the SacrumPelvis joint in the available outputs. Does this mean that I need to define a specific measurement to obtain the lumbar joint moments?
Additionally, I have another question about the spine model. Based on de Zee et al. (2007), I understood that the spine model consists of seven rigid segments: the pelvis, five lumbar vertebrae, and a lumped thoracic part. However, I noticed that the current model includes a spherical joint between the sacrum and pelvis. Does this imply that the sacrum-pelvis connection is no longer modeled as a rigid segment? Is there any recent publication describing the updated spine model? Also, are the RhythmCoefficients still based on Wong et al. (2006)? I noticed that a small section in the model refers to the sacrum-pelvis joint.
I have an additional question related to this post. I have already run the simulations but did not define any measurement for the net intervertebral moments. If these values are not included in the default output of AnyBody, do I need to rerun the simulations with new measurements defined, or is there a way to extract these results from the simulations that have already been run?
The spine rhythm coefficients in AMMR 3x and backwards has to my knowledge not changed since its original implementation.
I do not think the coefficients are in any of the papers about the model, I am sorry.
The best description of how the rhythm originates can be seen here in this old powerpoint presentation Spine Rhythm Presentation , it does however not display the coefficients.
Concerning the sacrum-pelvic joint, it is part of the rhythm, but the coefficient is small so it does move a lot.
Concerning lumbar moments, unfortunately there is no measure yet built into AMMR to measure these moments, due to the complications with the abdominal pressure model setting up this measure is not trivial. A crude way is to run the trunk with out muscles and look at the torque actuators, they will represent this.
About re-running, short answer is yes this is needed, if you add new measure to the model you need to re-run, only simple script equations building on loaded output may not require a run