# Wrist Muscle Question

Could someone just refresh my memory as to how the wrist muscle file works
exactly? I am currently applying a force to the palm joint of: (-82.3, 82.14,
21.2) Newtons. If I have a scenario where, after running the inverse dynamics
analysis, my outputs at a particular time are as follows (obviously when I
change my force input, the resulting muscle forces changes):

WristFlexionMuscle = 2.16509
WristExtensionMuscle = 0.0
WristAbductionMuscle = 0.0

Does this mean that at the wrist joint there is an x-direction force of 2.16509,
and a y-direction force of 1.317015? Is this in global or local? Where is the
z-direction force - there is a z-force input? What I am trying to do is
calculate the joint forces (by hand) according to the muscle outputs, and
compare these results to the joint reaction forces calculated by AnyBody.
However, I get stuck right at the beginning because I can?t quite figure out how
the wrist muscle is ?attached? or how the wrist joint force is being calculated.
And does the glove folder have anything to do with what I?m looking at? I?m not
really ?gripping? anything so I haven?t even investigated the glove folders?

I hope this isn?t a dumb question, I?m just a little confused?

Thank you for all your help,
Sarah

Hi Sarah

It is a good question.

The muscle forces you get is the wrist moments not forces, so the
numbers you have listed are the moments generated by AnyGeneral
muscles attached to the wrist joint.

The wrist joint has been equipped with moment generating
AnyGeneralMuscles because there are currently no ordinary muscles
spanning this joint in the model, in the file “WristMuscle.any” you
can see how it was implemented. It is done using AnyGeneralMuscles
if these are applied to a linear measure they supply force and if
applied to a rotational measure they supply moment. These moment
generating muscles is determined as a part of the normal muscle
recruiment problem.

In the joint folder you can find the wrist joint and her you will
find a universal joint with three reactions forces and one moment
reaction available.

If you have supplied your force directly to the hand segment you do
not need to think about the glove segment since it will be unloaded
and could essentially be removed from your model i guess.

Best regards
SÃ¸ren, AnyBody Support

— In anyscript@yahoogroups.com, “Sarah R. Sullivan” <sarsulli@…>
wrote:
>
> Could someone just refresh my memory as to how the wrist muscle
file works exactly? I am currently applying a force to the palm
joint of: (-82.3, 82.14, 21.2) Newtons. If I have a scenario where,
after running the inverse dynamics analysis, my outputs at a
particular time are as follows (obviously when I change my force
input, the resulting muscle forces changes):
>
> WristFlexionMuscle = 2.16509
> WristExtensionMuscle = 0.0
> WristAbductionMuscle = 0.0
>
> Does this mean that at the wrist joint there is an x-direction
force of 2.16509, and a y-direction force of 1.317015? Is this in
global or local? Where is the z-direction force - there is a z-
force input? What I am trying to do is calculate the joint forces
(by hand) according to the muscle outputs, and compare these results
to the joint reaction forces calculated by AnyBody. However, I get
stuck right at the beginning because I can?t quite figure out how
the wrist muscle is ?attached? or how the wrist joint force is being
calculated. And does the glove folder have anything to do with what
I?m looking at? I?m not really ?gripping? anything so I haven?t
even investigated the glove folders?
>
> I hope this isn?t a dumb question, I?m just a little confused?
>
> Thank you for all your help,
> Sarah
>

Thanks for your help, I really appreciate it. I think I understand where to now
find joint forces and moments. Just to clarify though, when I go to the model
tree and follow the following path and double-click on Fout:

Main --> MyArm --> HumanModel --> Right --> ShoulderArm --> Jnt --> WristJoint
–> Constraints --> Reaction --> Fout

I get an output of: {-109.9579, -33.0558, 9.893213, 0.3731783};

So the first three numbers are the Fx, Fy, and Fz at the wrist joint, and the
fourth number is the moment. If this is the case, I am assuming that these
outputs are in local coordinates, correct? To view these outputs in global
coordinates, I can just change the Ref in the BRep Jnt file, right?

Sarah

-----Original Message-----

> Date: Wed Jul 11 04:42:26 EDT 2007
> From: “AnyBody Support” <support@anybodytech.com>
> Subject: [AnyScript] Re: Wrist Muscle Question
> To: anyscript@yahoogroups.com
>
> Hi Sarah
>
> It is a good question.
>
> The muscle forces you get is the wrist moments not forces, so the
> numbers you have listed are the moments generated by AnyGeneral
> muscles attached to the wrist joint.
>
> The wrist joint has been equipped with moment generating
> AnyGeneralMuscles because there are currently no ordinary muscles
> spanning this joint in the model, in the file “WristMuscle.any” you
> can see how it was implemented. It is done using AnyGeneralMuscles
> if these are applied to a linear measure they supply force and if
> applied to a rotational measure they supply moment. These moment
> generating muscles is determined as a part of the normal muscle
> recruiment problem.
>
> In the joint folder you can find the wrist joint and her you will
> find a universal joint with three reactions forces and one moment
> reaction available.
>
> If you have supplied your force directly to the hand segment you do
> not need to think about the glove segment since it will be unloaded
> and could essentially be removed from your model i guess.
>
>
> Best regards
> SÃ¸ren, AnyBody Support
>
> — In anyscript@yahoogroups.com, “Sarah R. Sullivan” <sarsulli@…>
> wrote:
> >
> > Could someone just refresh my memory as to how the wrist muscle
> file works exactly? I am currently applying a force to the palm
> joint of: (-82.3, 82.14, 21.2) Newtons. If I have a scenario where,
> after running the inverse dynamics analysis, my outputs at a
> particular time are as follows (obviously when I change my force
> input, the resulting muscle forces changes):
> >
> > WristFlexionMuscle = 2.16509
> > WristExtensionMuscle = 0.0
> > WristAbductionMuscle = 0.0
> >
> > Does this mean that at the wrist joint there is an x-direction
> force of 2.16509, and a y-direction force of 1.317015? Is this in
> global or local? Where is the z-direction force - there is a z-
> force input? What I am trying to do is calculate the joint forces
> (by hand) according to the muscle outputs, and compare these results
> to the joint reaction forces calculated by AnyBody. However, I get
> stuck right at the beginning because I can?t quite figure out how
> the wrist muscle is ?attached? or how the wrist joint force is being
> calculated. And does the glove folder have anything to do with what
> I?m looking at? I?m not really ?gripping? anything so I haven?t
> even investigated the glove folders?
> >
> > I hope this isn?t a dumb question, I?m just a little confused?
> >
> > Thank you for all your help,
> > Sarah
> >
>
>

Hi Sarah

To me it sounds all right:)

Best regards
Christian, AnyBody Support

— In anyscript@yahoogroups.com, “Sarah R. Sullivan” <sarsulli@…>
wrote:
>
>
> Thanks for your help, I really appreciate it. I think I understand
where to now find joint forces and moments. Just to clarify though,
when I go to the model tree and follow the following path and
double-click on Fout:
>
> Main --> MyArm --> HumanModel --> Right --> ShoulderArm --> Jnt -->
WristJoint --> Constraints --> Reaction --> Fout
>
> I get an output of: {-109.9579, -33.0558, 9.893213, 0.3731783};
>
> So the first three numbers are the Fx, Fy, and Fz at the wrist
joint, and the fourth number is the moment. If this is the case, I am
assuming that these outputs are in local coordinates, correct? To
view these outputs in global coordinates, I can just change the Ref in
the BRep Jnt file, right?
>
> Thanks again for your help,
> Sarah
>
>
>
>
> -----Original Message-----
>
> > Date: Wed Jul 11 04:42:26 EDT 2007
> > From: “AnyBody Support” <support@…>
> > Subject: [AnyScript] Re: Wrist Muscle Question
> > To: anyscript@yahoogroups.com
> >
> > Hi Sarah
> >
> > It is a good question.
> >
> > The muscle forces you get is the wrist moments not forces, so the
> > numbers you have listed are the moments generated by AnyGeneral
> > muscles attached to the wrist joint.
> >
> > The wrist joint has been equipped with moment generating
> > AnyGeneralMuscles because there are currently no ordinary muscles
> > spanning this joint in the model, in the file “WristMuscle.any” you
> > can see how it was implemented. It is done using AnyGeneralMuscles
> > if these are applied to a linear measure they supply force and if
> > applied to a rotational measure they supply moment. These moment
> > generating muscles is determined as a part of the normal muscle
> > recruiment problem.
> >
> > In the joint folder you can find the wrist joint and her you will
> > find a universal joint with three reactions forces and one moment
> > reaction available.
> >
> > If you have supplied your force directly to the hand segment you do
> > not need to think about the glove segment since it will be unloaded
> > and could essentially be removed from your model i guess.
> >
> >
> > Best regards
> > SÃ¯Â¿Â½ren, AnyBody Support
> >
> > — In anyscript@yahoogroups.com, “Sarah R. Sullivan” <sarsulli@>
> > wrote:
> > >
> > > Could someone just refresh my memory as to how the wrist muscle
> > file works exactly? I am currently applying a force to the palm
> > joint of: (-82.3, 82.14, 21.2) Newtons. If I have a scenario where,
> > after running the inverse dynamics analysis, my outputs at a
> > particular time are as follows (obviously when I change my force
> > input, the resulting muscle forces changes):
> > >
> > > WristFlexionMuscle = 2.16509
> > > WristExtensionMuscle = 0.0
> > > WristAdductionMuscle = 1.317015
> > > WristAbductionMuscle = 0.0
> > >
> > > Does this mean that at the wrist joint there is an x-direction
> > force of 2.16509, and a y-direction force of 1.317015? Is this in
> > global or local? Where is the z-direction force - there is a z-
> > force input? What I am trying to do is calculate the joint forces
> > (by hand) according to the muscle outputs, and compare these results
> > to the joint reaction forces calculated by AnyBody. However, I get
> > stuck right at the beginning because I can?t quite figure out how
> > the wrist muscle is ?attached? or how the wrist joint force is being
> > calculated. And does the glove folder have anything to do with what
> > I?m looking at? I?m not really ?gripping? anything so I haven?t
> > even investigated the glove folders?
> > >
> > > I hope this isn?t a dumb question, I?m just a little confused?
> > >
> > > Thank you for all your help,
> > > Sarah
> > >
> >
> >
>

Sorry to both you again, but just when you thought you were done with me…

I thought of another question!

When I get joint force outputs from the path I mentioned below (or similarly for
the elbow), what coordinate frame are the Fx, Fy, and Fz in? For example if my
wrist joint outputs are:

{-109.9579, -33.0558, 9.893213, 0.3731783},

Are the forces in reference to the hand or radius? And likewise for the elbow
joint, are the resulting forces in reference to the humerus or ulna reference
frame?

I feel like this should be inherent, but I am a bit confused…

As always, thanks for your help,
Sarah

-----Original Message-----

> Date: Mon Jul 16 06:45:00 EDT 2007
> From: “AnyBody Support” <support@anybodytech.com>
> Subject: [AnyScript] Re: Wrist Muscle Question
> To: anyscript@yahoogroups.com
>
> Hi Sarah
>
> To me it sounds all right:)
>
> Best regards
> Christian, AnyBody Support
>
> — In anyscript@yahoogroups.com, “Sarah R. Sullivan” <sarsulli@…>
> wrote:
> >
> >
> > Thanks for your help, I really appreciate it. I think I understand
> where to now find joint forces and moments. Just to clarify though,
> when I go to the model tree and follow the following path and
> double-click on Fout:
> >
> > Main --> MyArm --> HumanModel --> Right --> ShoulderArm --> Jnt -->
> WristJoint --> Constraints --> Reaction --> Fout
> >
> > I get an output of: {-109.9579, -33.0558, 9.893213, 0.3731783};
> >
> > So the first three numbers are the Fx, Fy, and Fz at the wrist
> joint, and the fourth number is the moment. If this is the case, I am
> assuming that these outputs are in local coordinates, correct? To
> view these outputs in global coordinates, I can just change the Ref in
> the BRep Jnt file, right?
> >
> > Thanks again for your help,
> > Sarah
> >
> >
> >
> >
> > -----Original Message-----
> >
> > > Date: Wed Jul 11 04:42:26 EDT 2007
> > > From: “AnyBody Support” <support@…>
> > > Subject: [AnyScript] Re: Wrist Muscle Question
> > > To: anyscript@yahoogroups.com
> > >
> > > Hi Sarah
> > >
> > > It is a good question.
> > >
> > > The muscle forces you get is the wrist moments not forces, so the
> > > numbers you have listed are the moments generated by AnyGeneral
> > > muscles attached to the wrist joint.
> > >
> > > The wrist joint has been equipped with moment generating
> > > AnyGeneralMuscles because there are currently no ordinary muscles
> > > spanning this joint in the model, in the file “WristMuscle.any” you
> > > can see how it was implemented. It is done using AnyGeneralMuscles
> > > if these are applied to a linear measure they supply force and if
> > > applied to a rotational measure they supply moment. These moment
> > > generating muscles is determined as a part of the normal muscle
> > > recruiment problem.
> > >
> > > In the joint folder you can find the wrist joint and her you will
> > > find a universal joint with three reactions forces and one moment
> > > reaction available.
> > >
> > > If you have supplied your force directly to the hand segment you do
> > > not need to think about the glove segment since it will be unloaded
> > > and could essentially be removed from your model i guess.
> > >
> > >
> > > Best regards
> > > SÃ¯Â¿Â½ren, AnyBody Support
> > >
> > > — In anyscript@yahoogroups.com, “Sarah R. Sullivan” <sarsulli@>
> > > wrote:
> > > >
> > > > Could someone just refresh my memory as to how the wrist muscle
> > > file works exactly? I am currently applying a force to the palm
> > > joint of: (-82.3, 82.14, 21.2) Newtons. If I have a scenario where,
> > > after running the inverse dynamics analysis, my outputs at a
> > > particular time are as follows (obviously when I change my force
> > > input, the resulting muscle forces changes):
> > > >
> > > > WristFlexionMuscle = 2.16509
> > > > WristExtensionMuscle = 0.0
> > > > WristAdductionMuscle = 1.317015
> > > > WristAbductionMuscle = 0.0
> > > >
> > > > Does this mean that at the wrist joint there is an x-direction
> > > force of 2.16509, and a y-direction force of 1.317015? Is this in
> > > global or local? Where is the z-direction force - there is a z-
> > > force input? What I am trying to do is calculate the joint forces
> > > (by hand) according to the muscle outputs, and compare these results
> > > to the joint reaction forces calculated by AnyBody. However, I get
> > > stuck right at the beginning because I can?t quite figure out how
> > > the wrist muscle is ?attached? or how the wrist joint force is being
> > > calculated. And does the glove folder have anything to do with what
> > > I?m looking at? I?m not really ?gripping? anything so I haven?t
> > > even investigated the glove folders?
> > > >
> > > > I hope this isn?t a dumb question, I?m just a little confused?
> > > >
> > > > Thank you for all your help,
> > > > Sarah
> > > >
> > >
> > >
> >
>
>

Hi Sarah

The reaction forces of the joint are given in the first mentioned
reference frame of the joint. In this case it is the coordinate
system of the wrist node on the radius bone.

So in general this can be seen in the Jnt.any file.

Best regards
SÃ¸ren, AnyBody Support

— In anyscript@yahoogroups.com, “Sarah R. Sullivan” <sarsulli@…>
wrote:
>
> Sorry to both you again, but just when you thought you were done
with me…
>
> I thought of another question!
>
> When I get joint force outputs from the path I mentioned below (or
similarly for the elbow), what coordinate frame are the Fx, Fy, and
Fz in? For example if my wrist joint outputs are:
>
> {-109.9579, -33.0558, 9.893213, 0.3731783},
>
> Are the forces in reference to the hand or radius? And likewise
for the elbow joint, are the resulting forces in reference to the
humerus or ulna reference frame?
>
> I feel like this should be inherent, but I am a bit confused…
>
> As always, thanks for your help,
> Sarah
>
> -----Original Message-----
>
> > Date: Mon Jul 16 06:45:00 EDT 2007
> > From: “AnyBody Support” <support@…>
> > Subject: [AnyScript] Re: Wrist Muscle Question
> > To: anyscript@yahoogroups.com
> >
> > Hi Sarah
> >
> > To me it sounds all right:)
> >
> > Best regards
> > Christian, AnyBody Support
> >
> > — In anyscript@yahoogroups.com, “Sarah R. Sullivan” <sarsulli@>
> > wrote:
> > >
> > >
> > > Thanks for your help, I really appreciate it. I think I
understand
> > where to now find joint forces and moments. Just to clarify
though,
> > when I go to the model tree and follow the following path and
> > double-click on Fout:
> > >
> > > Main --> MyArm --> HumanModel --> Right --> ShoulderArm -->
Jnt -->
> > WristJoint --> Constraints --> Reaction --> Fout
> > >
> > > I get an output of: {-109.9579, -33.0558, 9.893213, 0.3731783};
> > >
> > > So the first three numbers are the Fx, Fy, and Fz at the wrist
> > joint, and the fourth number is the moment. If this is the
case, I am
> > assuming that these outputs are in local coordinates, correct?
To
> > view these outputs in global coordinates, I can just change the
Ref in
> > the BRep Jnt file, right?
> > >
> > > Thanks again for your help,
> > > Sarah
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > >
> > > > Date: Wed Jul 11 04:42:26 EDT 2007
> > > > From: “AnyBody Support” <support@>
> > > > Subject: [AnyScript] Re: Wrist Muscle Question
> > > > To: anyscript@yahoogroups.com
> > > >
> > > > Hi Sarah
> > > >
> > > > It is a good question.
> > > >
> > > > The muscle forces you get is the wrist moments not forces,
so the
> > > > numbers you have listed are the moments generated by
AnyGeneral
> > > > muscles attached to the wrist joint.
> > > >
> > > > The wrist joint has been equipped with moment generating
> > > > AnyGeneralMuscles because there are currently no ordinary
muscles
> > > > spanning this joint in the model, in the
file “WristMuscle.any” you
> > > > can see how it was implemented. It is done using
AnyGeneralMuscles
> > > > if these are applied to a linear measure they supply force
and if
> > > > applied to a rotational measure they supply moment. These
moment
> > > > generating muscles is determined as a part of the normal
muscle
> > > > recruiment problem.
> > > >
> > > > In the joint folder you can find the wrist joint and her you
will
> > > > find a universal joint with three reactions forces and one
moment
> > > > reaction available.
> > > >
> > > > If you have supplied your force directly to the hand
segment you do
> > > > not need to think about the glove segment since it will be
> > > > and could essentially be removed from your model i guess.
> > > >
again
> > > >
> > > > Best regards
> > > > SÃ¯Â¿Â½ren, AnyBody Support
> > > >
> > > > — In anyscript@yahoogroups.com, “Sarah R. Sullivan”
<sarsulli@>
> > > > wrote:
> > > > >
> > > > > Could someone just refresh my memory as to how the wrist
muscle
> > > > file works exactly? I am currently applying a force to the
palm
> > > > joint of: (-82.3, 82.14, 21.2) Newtons. If I have a
scenario where,
> > > > after running the inverse dynamics analysis, my outputs at a
> > > > particular time are as follows (obviously when I change my
force
> > > > input, the resulting muscle forces changes):
> > > > >
> > > > > WristFlexionMuscle = 2.16509
> > > > > WristExtensionMuscle = 0.0
> > > > > WristAdductionMuscle = 1.317015
> > > > > WristAbductionMuscle = 0.0
> > > > >
> > > > > Does this mean that at the wrist joint there is an x-
direction
> > > > force of 2.16509, and a y-direction force of 1.317015? Is
this in
> > > > global or local? Where is the z-direction force - there is
a z-
> > > > force input? What I am trying to do is calculate the joint
forces
> > > > (by hand) according to the muscle outputs, and compare these
results
> > > > to the joint reaction forces calculated by AnyBody.
However, I get
> > > > stuck right at the beginning because I can?t quite figure
out how
> > > > the wrist muscle is ?attached? or how the wrist joint force
is being
> > > > calculated. And does the glove folder have anything to do
with what
> > > > I?m looking at? I?m not really ?gripping? anything so I
haven?t
> > > > even investigated the glove folders?
> > > > >
> > > > > I hope this isn?t a dumb question, I?m just a little
confused?
> > > > >
> > > > > Thank you for all your help,
> > > > > Sarah
> > > > >
> > > >
> > > >
> > >
> >
> >
>