# Translated Muscle Forces

Hi,

to do some FE Analysis on the femur, I’ve translated the muscle forces
from the global coordinate system to the local femur system.
Unfortunately the amplitude of the muscle forces differ within the two
coordinate systems, e.g. for time step 0.3 the vastus lateralis in its
origin point is 735 N in the global coordinate system and about 1000 N
in the local coordinate system.

How can that be?

I’ve attached the modell in the file folder:

Upstair_Thomas.zip

Best regards

Thomas

Hi Thomas,

I have run the model but could not see this difference in the amplitude of
muscle forces.

Here is the calculation of the force amplitude for the vastus lateralis I
made from the values of the ChartFX window (step 7, 0.3 second):

Global (folder Measures): (397^2 + 644^2 + 150^2)^0.5 = 771.26 N

Local (folder FEOutput): (60.7^2 + 763^2 + 89.7^2)^0.5 = 770.64 N

Of course there is a very small error due to the calculation made without
decimals. But otherwise the amplitude is the same. And I checked some few
more steps and there are ok too.

So I’m quite surprised that you get different values. Could you please give
more details about how you get them, where did you read them, which
calculation have you done?

Best regards,

Sylvain, AnyBody Support

From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf
Of knox40
Sent: 31. oktober 2008 12:18
To: anyscript@yahoogroups.com
Subject: [AnyScript] Translated Muscle Forces

Hi,

to do some FE Analysis on the femur, I’ve translated the muscle forces
from the global coordinate system to the local femur system.
Unfortunately the amplitude of the muscle forces differ within the two
coordinate systems, e.g. for time step 0.3 the vastus lateralis in its
origin point is 735 N in the global coordinate system and about 1000 N
in the local coordinate system.

How can that be?

I’ve attached the modell in the file folder:

Upstair_Thomas.zip

Best regards

Thomas

[Non-text portions of this message have been removed]

Hello Thomas,

One additional remark: In the current version of AnyBody 3.0.3. is also a
feature named AnyMechOutputFileForceExport, this allows you to export all
forces acting on a single segment. All forces are given in the same
coordinate system (global).

Best regards,

Sebastian

From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf
Of knox40
Sent: 31. oktober 2008 12:18
To: anyscript@yahoogroups.com
Subject: [AnyScript] Translated Muscle Forces

Hi,

to do some FE Analysis on the femur, I’ve translated the muscle forces
from the global coordinate system to the local femur system.
Unfortunately the amplitude of the muscle forces differ within the two
coordinate systems, e.g. for time step 0.3 the vastus lateralis in its
origin point is 735 N in the global coordinate system and about 1000 N
in the local coordinate system.

How can that be?

I’ve attached the modell in the file folder:

Upstair_Thomas.zip

Best regards

Thomas

[Non-text portions of this message have been removed]

Hi Sylvain,

I’ve checked again and here is my calculation for the force
amplitude for the vastus lateralis I:
(also made from the ChartFX window step7, 0.3 seconds)

Global (folder Measures): (378^2 + 614^2 + 143^2)^0.5 = 735 N

Local (folder FEOutput): (174^2 + 1020^2 + 99.5^2)^0.5 = 1040 N?

I have used the AnyBody Version 2.0.1 because I have created the
model in this version. Is there a bug in Version 2.x?

In the newest Version 3 there are some formating differences and it
What do I have to change in the script to load the model on version
3.x?

Best regards,

Thomas

— In anyscript@yahoogroups.com, AnyScript Support
<anyscriptsup@…> wrote:
>
> Hi Thomas,
>
>
>
> I have run the model but could not see this difference in the
amplitude of
> muscle forces.
>
> Here is the calculation of the force amplitude for the vastus
lateralis I
> made from the values of the ChartFX window (step 7, 0.3 second):
>
> Global (folder Measures): (397^2 + 644^2 + 150^2)^0.5 = 771.26 N
>
> Local (folder FEOutput): (60.7^2 + 763^2 + 89.7^2)^0.5 = 770.64 N
>
>
>
> Of course there is a very small error due to the calculation made
without
> decimals. But otherwise the amplitude is the same. And I checked
some few
> more steps and there are ok too.
>
> So I’m quite surprised that you get different values. Could you
> more details about how you get them, where did you read them, which
> calculation have you done?
>
>
>
> Best regards,
>
> Sylvain, AnyBody Support
>
>
>
>
>
> _____
>
> From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com]
On Behalf
> Of knox40
> Sent: 31. oktober 2008 12:18
> To: anyscript@yahoogroups.com
> Subject: [AnyScript] Translated Muscle Forces
>
>
>
> Hi,
>
> to do some FE Analysis on the femur, I’ve translated the muscle
forces
> from the global coordinate system to the local femur system.
> Unfortunately the amplitude of the muscle forces differ within the
two
> coordinate systems, e.g. for time step 0.3 the vastus lateralis in
its
> origin point is 735 N in the global coordinate system and about
1000 N
> in the local coordinate system.
>
> How can that be?
>
> I’ve attached the modell in the file folder:
>
> Upstair_Thomas.zip
>
> Best regards
>
> Thomas
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

Hi Thomas,

Well it sounds like it could be a bug in version 2.x that has been corrected
since then, as I ran the model in version 3.x and the values was correct.

Will you try to run it in version 3.x? The modification to do is the
following: in the JointsAndDrivers file when using the ContactSurfaceLinPush
for the foot conditional contact, the Direction vector has to be defined as
an AnyIntArray :

AnyIntArray Direction={1,0,2}; //first element gives normal direction

Please keep us updated on whether the results are better or not.

Best regards,

Sylvain, AnyBody Support

From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf
Of knox40
Sent: 5. november 2008 12:03
To: anyscript@yahoogroups.com
Subject: [AnyScript] Re: Translated Muscle Forces

Hi Sylvain,

I’ve checked again and here is my calculation for the force
amplitude for the vastus lateralis I:
(also made from the ChartFX window step7, 0.3 seconds)

Global (folder Measures): (378^2 + 614^2 + 143^2)^0.5 = 735 N

Local (folder FEOutput): (174^2 + 1020^2 + 99.5^2)^0.5 = 1040 N?

I have used the AnyBody Version 2.0.1 because I have created the
model in this version. Is there a bug in Version 2.x?

In the newest Version 3 there are some formating differences and it
What do I have to change in the script to load the model on version
3.x?

Best regards,

Thomas

— In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com,
AnyScript Support
<anyscriptsup@…> wrote:
>
> Hi Thomas,
>
>
>
> I have run the model but could not see this difference in the
amplitude of
> muscle forces.
>
> Here is the calculation of the force amplitude for the vastus
lateralis I
> made from the values of the ChartFX window (step 7, 0.3 second):
>
> Global (folder Measures): (397^2 + 644^2 + 150^2)^0.5 = 771.26 N
>
> Local (folder FEOutput): (60.7^2 + 763^2 + 89.7^2)^0.5 = 770.64 N
>
>
>
> Of course there is a very small error due to the calculation made
without
> decimals. But otherwise the amplitude is the same. And I checked
some few
> more steps and there are ok too.
>
> So I’m quite surprised that you get different values. Could you
> more details about how you get them, where did you read them, which
> calculation have you done?
>
>
>
> Best regards,
>
> Sylvain, AnyBody Support
>
>
>
>
>
> _____
>
> From: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com
[mailto:anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com]
On Behalf
> Of knox40
> Sent: 31. oktober 2008 12:18
> To: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com> ps.com
> Subject: [AnyScript] Translated Muscle Forces
>
>
>
> Hi,
>
> to do some FE Analysis on the femur, I’ve translated the muscle
forces
> from the global coordinate system to the local femur system.
> Unfortunately the amplitude of the muscle forces differ within the
two
> coordinate systems, e.g. for time step 0.3 the vastus lateralis in
its
> origin point is 735 N in the global coordinate system and about
1000 N
> in the local coordinate system.
>
> How can that be?
>
> I’ve attached the modell in the file folder:
>
> Upstair_Thomas.zip
>
> Best regards
>
> Thomas
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

[Non-text portions of this message have been removed]

Hi Sylvain,

sorry for answering so late but I was busy with some other work the
last few weeks.

By using the version 3.x the total values are the same for the local
and global coordinate system. Thus it seems that there was a bug in
version 2.x.

Now I want to look at the influence of the different muscle models:

AnyMuscleModel
AnyMuscleModel3E
AnyMuscleModel2ELin

Therefore I had a look at Lesson 5 of the Tutorial with the quite
good description of these muscle models. But there are some
questions left for me:

1. Are these 3 muscle models generally used as today’s state of the
art?

models?

3. How do I choose which muscle model is the best for my model? Is
there a recommendation for a prefered muscle model? -I know that the
results are only as good as the input data but as you already
provide values for the AnyMuscleModel3E should I therefor choose
this as the best?

4. As the RecruitmentSolver is divided into a linear and quadratic
programming algorithm, which solver type is more trustful? In
general the computation time is not that much for the Anybody models
and is it therfore better to choose the quadratic solver?

…a lot of questions but I’m just a beginner in muscle modelling.

Thank you.

Best regards

Thomas

— In anyscript@yahoogroups.com, AnyScript Support
<anyscriptsup@…> wrote:
>
> Hi Thomas,
>
>
>
> Well it sounds like it could be a bug in version 2.x that has been
corrected
> since then, as I ran the model in version 3.x and the values was
correct.
>
>
>
> Will you try to run it in version 3.x? The modification to do is
the
> following: in the JointsAndDrivers file when using the
ContactSurfaceLinPush
> for the foot conditional contact, the Direction vector has to be
defined as
> an AnyIntArray :
>
> AnyIntArray Direction={1,0,2}; //first element gives normal
direction
>
>
>
> Please keep us updated on whether the results are better or not.
>
>
>
> Best regards,
>
> Sylvain, AnyBody Support
>
>
>
>
>
> _____
>
> From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com]
On Behalf
> Of knox40
> Sent: 5. november 2008 12:03
> To: anyscript@yahoogroups.com
> Subject: [AnyScript] Re: Translated Muscle Forces
>
>
>
> Hi Sylvain,
>
> I’ve checked again and here is my calculation for the force
> amplitude for the vastus lateralis I:
> (also made from the ChartFX window step7, 0.3 seconds)
>
> Global (folder Measures): (378^2 + 614^2 + 143^2)^0.5 = 735 N
>
> Local (folder FEOutput): (174^2 + 1020^2 + 99.5^2)^0.5 = 1040 N?
>
> I have used the AnyBody Version 2.0.1 because I have created the
> model in this version. Is there a bug in Version 2.x?
>
> In the newest Version 3 there are some formating differences and
it
> What do I have to change in the script to load the model on
version
> 3.x?
>
>
> Best regards,
>
> Thomas
>
> — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com,
> AnyScript Support
> <anyscriptsup@> wrote:
> >
> > Hi Thomas,
> >
> >
> >
> > I have run the model but could not see this difference in the
> amplitude of
> > muscle forces.
> >
> > Here is the calculation of the force amplitude for the vastus
> lateralis I
> > made from the values of the ChartFX window (step 7, 0.3 second):
> >
> > Global (folder Measures): (397^2 + 644^2 + 150^2)^0.5 = 771.26 N
> >
> > Local (folder FEOutput): (60.7^2 + 763^2 + 89.7^2)^0.5 = 770.64 N
> >
> >
> >
> > Of course there is a very small error due to the calculation
> without
> > decimals. But otherwise the amplitude is the same. And I checked
> some few
> > more steps and there are ok too.
> >
> > So I’m quite surprised that you get different values. Could you
> > more details about how you get them, where did you read them,
which
> > calculation have you done?
> >
> >
> >
> > Best regards,
> >
> > Sylvain, AnyBody Support
> >
> >
> >
> >
> >
> > _____
> >
> > From: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com
> [mailto:anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com]
> On Behalf
> > Of knox40
> > Sent: 31. oktober 2008 12:18
> > To: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com
> > Subject: [AnyScript] Translated Muscle Forces
> >
> >
> >
> > Hi,
> >
> > to do some FE Analysis on the femur, I’ve translated the muscle
> forces
> > from the global coordinate system to the local femur system.
> > Unfortunately the amplitude of the muscle forces differ within
the
> two
> > coordinate systems, e.g. for time step 0.3 the vastus lateralis
in
> its
> > origin point is 735 N in the global coordinate system and about
> 1000 N
> > in the local coordinate system.
> >
> > How can that be?
> >
> > I’ve attached the modell in the file folder:
> >
> > Upstair_Thomas.zip
> >
> > Best regards
> >
> > Thomas
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

Hi Thomas,

It is good to know that you got the correct muscle forces with version 3.x.

1. The AnyMuscleModel3E is definitely the most advanced model. It is used
quite a lot in our models. The AnyMuscleModel is also used a lot even if it
is a much simpler model than the AnyMuscleModel3E. This is because for most
situations the approximations are correct and lead to good enough results.

The AnyMuscleModel2Elin is actually not used in the repository and little
used in general. It is not as much detailed as the 3E model, and either does
not improve significantly the results from the simple model.

1. There is a list of publication on the web site, you have a look at it.
Here are some papers about the recruitment, but I think they deal more with
the solvers than with the muscle models themselves. Have a look:

Rasmussen, J., Damsgaard, M., Christensen, S.T. (2000): Inverse-inverse
dynamics simulation of musculo-skeletal systems. In: Prendergast, P.J., Lee,
T.C., Carr, A.J. (2000): Proceedings of the The 12th Conference of the
European Society of Biomechanics, Royal Academy of Medicine in Ireland, ISBN
0-9538809-0-7

Rasmussen, J., Damsgaard, M. & Voigt, M. (2001): Muscle recruitment by the
min/max criterion - a comparative numerical study. Journal of Biomechanics,
vol. 34, no. 3, pp. 409-415.

M. Damsgaard, S.T. Christensen, and J. Rasmussen (2001): An efficient
numerical algorithm for solving the muscle recruitment problem in inverse
dynamics simulations. International Society of Biomechanics, XVIIIth
Congress, July 8-13, 2001, Zurich, Switzerland.

1. The choice of the muscle model in some way depends of what you want to
investigate with your model. As we said the AnyMuscleModel3E is the more
advanced. It is good when dealing with passive forces or high velocity
motion. The risks with this muscle model are the numerous parameters and the
calibration needed, but we provided those with reliable data. If your model
has a quite slow motion and a small range of motion (muscle not stretched
too much) then the AnyMuscleModel3E is not necessarily needed and you can
play “secure” by using the AnyMuscleModel, it will do quite well.

2. The solvers are equally trustful. The choice between linear and quadratic
means a slightly different assumption on the behaviour of the muscle
recruitment. If you look in this tutorial
(http://www.anybodytech.com/691.0.html ) you will see the linear solution
gives more synergy to the muscles. In general we think the linear assumption
if closer to the reality.

Best regards,

Sylvain, AnyBody Support

From: anyscript@yahoogroups.com [mailto:anyscript@yahoogroups.com] On Behalf
Of knox40
Sent: 21. november 2008 16:11
To: anyscript@yahoogroups.com
Subject: [AnyScript] Re: Translated Muscle Forces

Hi Sylvain,

sorry for answering so late but I was busy with some other work the
last few weeks.

By using the version 3.x the total values are the same for the local
and global coordinate system. Thus it seems that there was a bug in
version 2.x.

Now I want to look at the influence of the different muscle models:

AnyMuscleModel
AnyMuscleModel3E
AnyMuscleModel2ELin

Therefore I had a look at Lesson 5 of the Tutorial with the quite
good description of these muscle models. But there are some
questions left for me:

1. Are these 3 muscle models generally used as today’s state of the
art?

models?

3. How do I choose which muscle model is the best for my model? Is
there a recommendation for a prefered muscle model? -I know that the
results are only as good as the input data but as you already
provide values for the AnyMuscleModel3E should I therefor choose
this as the best?

4. As the RecruitmentSolver is divided into a linear and quadratic
programming algorithm, which solver type is more trustful? In
general the computation time is not that much for the Anybody models
and is it therfore better to choose the quadratic solver?

…a lot of questions but I’m just a beginner in muscle modelling.

Thank you.

Best regards

Thomas

— In <mailto:anyscript%40yahoogroups.com> anyscript@yahoogroups.com,
AnyScript Support
<anyscriptsup@…> wrote:
>
> Hi Thomas,
>
>
>
> Well it sounds like it could be a bug in version 2.x that has been
corrected
> since then, as I ran the model in version 3.x and the values was
correct.
>
>
>
> Will you try to run it in version 3.x? The modification to do is
the
> following: in the JointsAndDrivers file when using the
ContactSurfaceLinPush
> for the foot conditional contact, the Direction vector has to be
defined as
> an AnyIntArray :
>
> AnyIntArray Direction={1,0,2}; //first element gives normal
direction
>
>
>
> Please keep us updated on whether the results are better or not.
>
>
>
> Best regards,
>
> Sylvain, AnyBody Support
>
>
>
>
>
> _____
>
> From: <mailto:anyscript%40yahoogroups.com> anyscript@yahoogroups.com
[mailto: <mailto:anyscript%40yahoogroups.com> anyscript@yahoogroups.com]
On Behalf
> Of knox40
> Sent: 5. november 2008 12:03
> To: <mailto:anyscript%40yahoogroups.com> anyscript@yahoogroups.com
> Subject: [AnyScript] Re: Translated Muscle Forces
>
>
>
> Hi Sylvain,
>
> I’ve checked again and here is my calculation for the force
> amplitude for the vastus lateralis I:
> (also made from the ChartFX window step7, 0.3 seconds)
>
> Global (folder Measures): (378^2 + 614^2 + 143^2)^0.5 = 735 N
>
> Local (folder FEOutput): (174^2 + 1020^2 + 99.5^2)^0.5 = 1040 N?
>
> I have used the AnyBody Version 2.0.1 because I have created the
> model in this version. Is there a bug in Version 2.x?
>
> In the newest Version 3 there are some formating differences and
it
> What do I have to change in the script to load the model on
version
> 3.x?
>
>
> Best regards,
>
> Thomas
>
> — In anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com,
> AnyScript Support
> <anyscriptsup@> wrote:
> >
> > Hi Thomas,
> >
> >
> >
> > I have run the model but could not see this difference in the
> amplitude of
> > muscle forces.
> >
> > Here is the calculation of the force amplitude for the vastus
> lateralis I
> > made from the values of the ChartFX window (step 7, 0.3 second):
> >
> > Global (folder Measures): (397^2 + 644^2 + 150^2)^0.5 = 771.26 N
> >
> > Local (folder FEOutput): (60.7^2 + 763^2 + 89.7^2)^0.5 = 770.64 N
> >
> >
> >
> > Of course there is a very small error due to the calculation
> without
> > decimals. But otherwise the amplitude is the same. And I checked
> some few
> > more steps and there are ok too.
> >
> > So I’m quite surprised that you get different values. Could you
> > more details about how you get them, where did you read them,
which
> > calculation have you done?
> >
> >
> >
> > Best regards,
> >
> > Sylvain, AnyBody Support
> >
> >
> >
> >
> >
> > _____
> >
> > From: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com
> [mailto:anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com]
> On Behalf
> > Of knox40
> > Sent: 31. oktober 2008 12:18
> > To: anyscript@yahoogrou <mailto:anyscript%40yahoogroups.com>
ps.com
> > Subject: [AnyScript] Translated Muscle Forces
> >
> >
> >
> > Hi,
> >
> > to do some FE Analysis on the femur, I’ve translated the muscle
> forces
> > from the global coordinate system to the local femur system.
> > Unfortunately the amplitude of the muscle forces differ within
the
> two
> > coordinate systems, e.g. for time step 0.3 the vastus lateralis
in
> its
> > origin point is 735 N in the global coordinate system and about
> 1000 N
> > in the local coordinate system.
> >
> > How can that be?
> >
> > I’ve attached the modell in the file folder:
> >
> > Upstair_Thomas.zip
> >
> > Best regards
> >
> > Thomas
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>
>
>
>
> [Non-text portions of this message have been removed]
>

[Non-text portions of this message have been removed]