Hi, I’m Sungwoo Park from South Korea. Thank you for helping me all the
time~
For this time, I have a question about muscleparameter F0 of
AnyMuscleModel. As far as I know, muscleparamere F0 is a maximum
muscle force if I ignore fiber length, am I right?
But in my stand-to-sit model, muscle forces after inversedynamics
analysis were way over muscleparameter values. For example, input
maximum muscle force of soleus is 2830N, but analyzed maximum muscle
force was almost 20000N. I have no idea what the problem is. It’ll be
very appreciated if you could help me with this. I posted my stand-to-
sit model file on the file board, just in case.
You are right the parameter F0 of the AnyMuscleModel is the maximum force of
the muscle. This parameter is constant in this muscle model.
However the system is able to recruit the muscle over their nominal
strength. Of course this is not possible in a real body. So when such an
over activity appears in a model it means that the muscles can’t carry the
load normally.
The cause of over activity can be bad boundary condition, excessive load or
too weak muscles for example. In your case the boundary conditions looks ok
to me. But I noticed that at some point of the analysis the Hamstring muscle
is going on the other side of the “hip” joint. It could be the cause of the
over activity because the muscle is not playing anymore its normal role. And
moreover this is the precise moment when the over activity appears.
If I remember well this is the same problem you had with the gluteus in your
previous posting. I suggest that you check that no other muscle is behaving
like this. To avoid it a good solution is to use via point so you can make
sure the muscle stays on its side of the joint.
Hi, I’m Sungwoo Park from South Korea. Thank you for helping me all the
time~
For this time, I have a question about muscleparameter F0 of
AnyMuscleModel. As far as I know, muscleparamere F0 is a maximum
muscle force if I ignore fiber length, am I right?
But in my stand-to-sit model, muscle forces after inversedynamics
analysis were way over muscleparameter values. For example, input
maximum muscle force of soleus is 2830N, but analyzed maximum muscle
force was almost 20000N. I have no idea what the problem is. It’ll be
very appreciated if you could help me with this. I posted my stand-to-
sit model file on the file board, just in case.
Thank you very much again~
Sincerely,
Sungwoo Park
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