Muscle Strain?

Hello Soren,

Is there a measure of much much a muscle contract during its motion?
In particular, the strian (change in length/original length ) of
muscle during a motion. How and where can I get those measure?

by the way, is the ‘bug’ in Anybody (in my previous model) being fixed
in the new AnyBody release?

Thanks,
Leng-Feng Lee

Hi Leng-Feng

There is no direct measure of the muscles strain as direct output
from the system, but you can easily compute from the standard output.

This small example shows how to do this for RectusFemoris if you
insert these lines in your study folder it will calculate the strain.

 AnyOutputFun Strain =
 {
   AnyFolder &ref=Main.Model.HumanModel.Left.Leg;
   AnyVar Lmt0= ref.MusPar.RectusFemorisPar.Lt0+cos

(ref.MusPar.RectusFemorisPar.Gammabar)
*ref.MusPar.RectusFemorisPar.Lfbar;
Val= ref.Mus.RectusFemoris.Lmt-Lmt0/Lmt0;
};

About the bug in the system, i am sorry that you have not been
updated on this matter before now. We have investigated the matter
further. The bug in the RotVector which is used by the revolute
joint is still present in the new system i am afraid, we are still
working on removing it. We are however convinced now that this error
can not be the root of any recruitment problems, which i have
written to you previously, and it will only occur in rare cases.

So the next question is then what caused your recruitment problems?
We have made some changes in the glove segment in the Arm3D folder
which makes the arm model more stable. These changes are part of the
new repository 6 which has been released recently. The changes
removes a “singular” point in the glove segment which seems to cause
recruitment problems in some cases. I think this will solve your
problems.

Best regards
Søren, AnyBody Support

— In anyscript@yahoogroups.com, “Leng-Feng Lee” <lengfenglee@…>
wrote:
>
> Hello Soren,
>
> Is there a measure of much much a muscle contract during its
motion?
> In particular, the strian (change in length/original length ) of
> muscle during a motion. How and where can I get those measure?
>
> by the way, is the ‘bug’ in Anybody (in my previous model) being
fixed
> in the new AnyBody release?
>
> Thanks,
> Leng-Feng Lee
>