muscle length measure and its parameter setting

[Linjie Wang]

Hi, there.

Does anyone know how to measure the muscle length with consideration of the wrap geometries through the GUI?

I am quite confused with the default parameters of each muscle properties (Millard muscle). When I changed the fiber length of some muscles by 10 times, my model can run CMC by 30 percenage of its soluion. So I am wondering if there is a way to visualize the muscle active fiber force length curve, fiber force length curve and tendon force length curve in order to check if they are the proper parameters to run CMC.

My last confusion is how the parameters (max isometric force, optimal fiber length, tendon slack length and pennation angel) of previous muscle types were defined. were they measured through experiment or tuned by modellers or averged statistically from a group of subjects?

Thanks,
Linjie

[Christopher Dembia]

CMC should print a partial states.sto file that contains the states up until CMC failed. You can use that states file in a Muscle Analysis (with the Analyze tool) to compute fiber length, etc.

[Christopher Dembia]

My last confusion is how the parameters (max isometric force, optimal fiber length, tendon slack length and pennation angel) of previous muscle types were defined. were they measured through experiment or tuned by modellers or averged statistically from a group of subjects?

You'll need to refer to the journal article that corresponds to your model. For example, https://www.ncbi.nlm.nih.gov/pubmed/27392337.

[Linjie Wang]

Thanks a lot, Chris.

[Linjie Wang]

Hi, Chris.

Do you mind if I ask the journal paper that referred to the musculotendon parameters for the JW model as the linked paper you just sent? Unforunately I have tried to find it for a long time.

Many thanks,
Linjie

[Thomas Uchida]

The paper can be found here: http://nmbl.stanford.edu/publication/

[Linjie Wang]

Thanks, Tom!