Dear AnyBody Team,
I’d like to get L5/S1 joint moments from an AnyBody standing model.
Joint reactions appear to give compressive forces, and there is
Sacrumpelvis reaction folder.
I though that sacrumpelvis reaction may be equivalent to L5/S1 joint
moments, yet values from sacrumpelvis reaction seem to be too small.
Is there a simple way to obtain L5/S1 joint moments?
Sincerely,
Sunwook
Hi Sunwook
I think the joint you are looking for is the L5Sacrum joint in the
model.
You are correct that joint reactions in the spine are the reaction
forces in the three directions, since spherical joints are being used.
If you are looking for the moment, you need to use a model without the
ordinary muscles on. so choos a bodymodel version
names “_NoMuscles.any”. This model have each dof equipped with moment
generating muscles, and you may read out the monments.
The reason why we have a SacrumPelvis reaction is because there are no
muscles to carry this reaction.
Please ask again if you have further questions.
Best regards
Søren, AnyBody Support
— In anyscript@yahoogroups.com, “ninegu_sun” <ninegu_sun@…> wrote:
>
> Dear AnyBody Team,
>
> I’d like to get L5/S1 joint moments from an AnyBody standing model.
> Joint reactions appear to give compressive forces, and there is
> Sacrumpelvis reaction folder.
> I though that sacrumpelvis reaction may be equivalent to L5/S1 joint
> moments, yet values from sacrumpelvis reaction seem to be too small.
>
> Is there a simple way to obtain L5/S1 joint moments?
>
> Sincerely,
> Sunwook
>
Thank you for the quick response.
I just checked JointMuscles folder to see positive and negative
muscle outputs for L5SacrumJnt, using the No_Muscle model.
The values appear to be still small (-39 Nm is the max value in all
DOFs), while compressive forces fall in a reasonable range.
Currently, I use the SpineTwoArms\BodyModel_NoMuscles.Any and apply
external forces on the hands (measured from loadcells).
Is it possibly because of external loads applied on the hands? I use
the same method for applying forceplate forces in Gait3D to apply
external forces on the hands.
Does this mean that I need to include a seperate folder to compute
L5/S1 moments?
Sincerely,
Sunwook
— In anyscript@yahoogroups.com, “AnyBody Support” <support@…>
wrote:
>
> Hi Sunwook
>
> I think the joint you are looking for is the L5Sacrum joint in the
> model.
>
> You are correct that joint reactions in the spine are the reaction
> forces in the three directions, since spherical joints are being
used.
>
> If you are looking for the moment, you need to use a model without
the
> ordinary muscles on. so choos a bodymodel version
> names “_NoMuscles.any”. This model have each dof equipped with
moment
> generating muscles, and you may read out the monments.
>
> The reason why we have a SacrumPelvis reaction is because there are
no
> muscles to carry this reaction.
>
> Please ask again if you have further questions.
>
> Best regards
> S?en, AnyBody Support
>
>
> — In anyscript@yahoogroups.com, “ninegu_sun” <ninegu_sun@> wrote:
> >
> > Dear AnyBody Team,
> >
> > I’d like to get L5/S1 joint moments from an AnyBody standing
model.
> > Joint reactions appear to give compressive forces, and there is
> > Sacrumpelvis reaction folder.
> > I though that sacrumpelvis reaction may be equivalent to L5/S1
joint
> > moments, yet values from sacrumpelvis reaction seem to be too
small.
> >
> > Is there a simple way to obtain L5/S1 joint moments?
> >
> > Sincerely,
> > Sunwook
> >
>
Hi Sunwook
I am not sure what was the size of you hand load so i can not judge
if the moment of 39Nm is ok or not. If the way you have applied the
forces are correct this moment should be ok, you should not need to
add extra stuff to read out the moment.
To check your model, you could try expluding your hand loads and
just add a AnyForce3D to the hands. This will create a constant
force vector and you will be able to check if the moments of the
joints are resonable. You may exclude gravity to get a more clear
picture if needed.
In principle it should be possible to load the hands in the same way
as the feet in the Gait3D model.
I hope this helps you move on
Best regards
Søren, AnyBody Support
— In anyscript@yahoogroups.com, “ninegu_sun” <ninegu_sun@…>
wrote:
>
> Thank you for the quick response.
>
> I just checked JointMuscles folder to see positive and negative
> muscle outputs for L5SacrumJnt, using the No_Muscle model.
> The values appear to be still small (-39 Nm is the max value in
all
> DOFs), while compressive forces fall in a reasonable range.
>
> Currently, I use the SpineTwoArms\BodyModel_NoMuscles.Any and
apply
> external forces on the hands (measured from loadcells).
>
> Is it possibly because of external loads applied on the hands? I
use
> the same method for applying forceplate forces in Gait3D to apply
> external forces on the hands.
>
> Does this mean that I need to include a seperate folder to compute
> L5/S1 moments?
>
> Sincerely,
> Sunwook
>
>
> — In anyscript@yahoogroups.com, “AnyBody Support” <support@>
> wrote:
> >
> > Hi Sunwook
> >
> > I think the joint you are looking for is the L5Sacrum joint in
the
> > model.
> >
> > You are correct that joint reactions in the spine are the
reaction
> > forces in the three directions, since spherical joints are being
> used.
> >
> > If you are looking for the moment, you need to use a model
without
> the
> > ordinary muscles on. so choos a bodymodel version
> > names “_NoMuscles.any”. This model have each dof equipped with
> moment
> > generating muscles, and you may read out the monments.
> >
> > The reason why we have a SacrumPelvis reaction is because there
are
> no
> > muscles to carry this reaction.
> >
> > Please ask again if you have further questions.
> >
> > Best regards
> > S?en, AnyBody Support
> >
> >
> > — In anyscript@yahoogroups.com, “ninegu_sun” <ninegu_sun@>
wrote:
> > >
> > > Dear AnyBody Team,
> > >
> > > I’d like to get L5/S1 joint moments from an AnyBody standing
> model.
> > > Joint reactions appear to give compressive forces, and there
is
> > > Sacrumpelvis reaction folder.
> > > I though that sacrumpelvis reaction may be equivalent to L5/S1
> joint
> > > moments, yet values from sacrumpelvis reaction seem to be too
> small.
> > >
> > > Is there a simple way to obtain L5/S1 joint moments?
> > >
> > > Sincerely,
> > > Sunwook
> > >
> >
>
Hello Soren,
Thank you for the inputs. As you suggested, I did simple checks.
First, I checked a fixed posture (i.e., 70 degree flexion) without
hand loads. Jointmuscle outputs for the L5/S1 are about 75 Nm. The
values are a bit lower than what I got from 3DSSPP. Yet, they are
acceptable.
Then, I repeated the same model with only one change in the motion
driver. I drove the trunk with measured angles (roughly flexion
angles range from 0 to 70 degree). For simplicity, lateral bending
and axial rotation were set to be 0. Then, Jointmuscle outputs for
the L5/S1 are found to be about 10 Nm.
I applied the same marker dirvers used in Gait3D. So, the reaction
type for marker drivers are set to be “off”.
I am not sure if driving posture with markers could cause this kind
of problem, since it appears that AnyBody gives acceptable values for
the static posture. I think I need more of your advice on this
problem to solve it.
Sincerely,
Sunwook
— In anyscript@yahoogroups.com, “AnyBody Support” <support@…>
wrote:
>
> Hi Sunwook
>
> I am not sure what was the size of you hand load so i can not
judge
> if the moment of 39Nm is ok or not. If the way you have applied the
> forces are correct this moment should be ok, you should not need to
> add extra stuff to read out the moment.
>
> To check your model, you could try expluding your hand loads and
> just add a AnyForce3D to the hands. This will create a constant
> force vector and you will be able to check if the moments of the
> joints are resonable. You may exclude gravity to get a more clear
> picture if needed.
>
> In principle it should be possible to load the hands in the same
way
> as the feet in the Gait3D model.
>
> I hope this helps you move on
>
> Best regards
> S?en, AnyBody Support
>
>
>
>
> — In anyscript@yahoogroups.com, “ninegu_sun” <ninegu_sun@>
> wrote:
> >
> > Thank you for the quick response.
> >
> > I just checked JointMuscles folder to see positive and negative
> > muscle outputs for L5SacrumJnt, using the No_Muscle model.
> > The values appear to be still small (-39 Nm is the max value in
> all
> > DOFs), while compressive forces fall in a reasonable range.
> >
> > Currently, I use the SpineTwoArms\BodyModel_NoMuscles.Any and
> apply
> > external forces on the hands (measured from loadcells).
> >
> > Is it possibly because of external loads applied on the hands? I
> use
> > the same method for applying forceplate forces in Gait3D to apply
> > external forces on the hands.
> >
> > Does this mean that I need to include a seperate folder to
compute
> > L5/S1 moments?
> >
> > Sincerely,
> > Sunwook
> >
> >
> > — In anyscript@yahoogroups.com, “AnyBody Support” <support@>
> > wrote:
> > >
> > > Hi Sunwook
> > >
> > > I think the joint you are looking for is the L5Sacrum joint in
> the
> > > model.
> > >
> > > You are correct that joint reactions in the spine are the
> reaction
> > > forces in the three directions, since spherical joints are
being
> > used.
> > >
> > > If you are looking for the moment, you need to use a model
> without
> > the
> > > ordinary muscles on. so choos a bodymodel version
> > > names “_NoMuscles.any”. This model have each dof equipped with
> > moment
> > > generating muscles, and you may read out the monments.
> > >
> > > The reason why we have a SacrumPelvis reaction is because there
> are
> > no
> > > muscles to carry this reaction.
> > >
> > > Please ask again if you have further questions.
> > >
> > > Best regards
> > > S?en, AnyBody Support
> > >
> > >
> > > — In anyscript@yahoogroups.com, “ninegu_sun” <ninegu_sun@>
> wrote:
> > > >
> > > > Dear AnyBody Team,
> > > >
> > > > I’d like to get L5/S1 joint moments from an AnyBody standing
> > model.
> > > > Joint reactions appear to give compressive forces, and there
> is
> > > > Sacrumpelvis reaction folder.
> > > > I though that sacrumpelvis reaction may be equivalent to
L5/S1
> > joint
> > > > moments, yet values from sacrumpelvis reaction seem to be too
> > small.
> > > >
> > > > Is there a simple way to obtain L5/S1 joint moments?
> > > >
> > > > Sincerely,
> > > > Sunwook
> > > >
> > >
> >
>
Hi Sunwook
It sounds as it could be a dynamic issue that kick in here maybee.
To check if this is the case please try to increase the tEnd value
of the analysis so that motion effectively becomes almost static.
The marker drivers should not cause any unloading of the spine
unless some the drivers have the reactions swithed on.
Please write again if this do not clearifies the matter
Best regards
Søren, AnyBody Support
— In anyscript@yahoogroups.com, “ninegu_sun” <ninegu_sun@…>
wrote:
>
> Hello Soren,
>
> Thank you for the inputs. As you suggested, I did simple checks.
>
> First, I checked a fixed posture (i.e., 70 degree flexion) without
> hand loads. Jointmuscle outputs for the L5/S1 are about 75 Nm.
The
> values are a bit lower than what I got from 3DSSPP. Yet, they are
> acceptable.
>
> Then, I repeated the same model with only one change in the motion
> driver. I drove the trunk with measured angles (roughly flexion
> angles range from 0 to 70 degree). For simplicity, lateral
bending
> and axial rotation were set to be 0. Then, Jointmuscle outputs
for
> the L5/S1 are found to be about 10 Nm.
>
> I applied the same marker dirvers used in Gait3D. So, the
reaction
> type for marker drivers are set to be “off”.
>
> I am not sure if driving posture with markers could cause this
kind
> of problem, since it appears that AnyBody gives acceptable values
for
> the static posture. I think I need more of your advice on this
> problem to solve it.
>
>
> Sincerely,
> Sunwook
>
>
>
> — In anyscript@yahoogroups.com, “AnyBody Support” <support@>
> wrote:
> >
> > Hi Sunwook
> >
> > I am not sure what was the size of you hand load so i can not
> judge
> > if the moment of 39Nm is ok or not. If the way you have applied
the
> > forces are correct this moment should be ok, you should not need
to
> > add extra stuff to read out the moment.
> >
> > To check your model, you could try expluding your hand loads and
> > just add a AnyForce3D to the hands. This will create a constant
> > force vector and you will be able to check if the moments of the
> > joints are resonable. You may exclude gravity to get a more
clear
> > picture if needed.
> >
> > In principle it should be possible to load the hands in the same
> way
> > as the feet in the Gait3D model.
> >
> > I hope this helps you move on
> >
> > Best regards
> > S?en, AnyBody Support
> >
> >
> >
> >
> > — In anyscript@yahoogroups.com, “ninegu_sun” <ninegu_sun@>
> > wrote:
> > >
> > > Thank you for the quick response.
> > >
> > > I just checked JointMuscles folder to see positive and
negative
> > > muscle outputs for L5SacrumJnt, using the No_Muscle model.
> > > The values appear to be still small (-39 Nm is the max value
in
> > all
> > > DOFs), while compressive forces fall in a reasonable range.
> > >
> > > Currently, I use the SpineTwoArms\BodyModel_NoMuscles.Any and
> > apply
> > > external forces on the hands (measured from loadcells).
> > >
> > > Is it possibly because of external loads applied on the
hands? I
> > use
> > > the same method for applying forceplate forces in Gait3D to
apply
> > > external forces on the hands.
> > >
> > > Does this mean that I need to include a seperate folder to
> compute
> > > L5/S1 moments?
> > >
> > > Sincerely,
> > > Sunwook
> > >
> > >
> > > — In anyscript@yahoogroups.com, “AnyBody Support” <support@>
> > > wrote:
> > > >
> > > > Hi Sunwook
> > > >
> > > > I think the joint you are looking for is the L5Sacrum joint
in
> > the
> > > > model.
> > > >
> > > > You are correct that joint reactions in the spine are the
> > reaction
> > > > forces in the three directions, since spherical joints are
> being
> > > used.
> > > >
> > > > If you are looking for the moment, you need to use a model
> > without
> > > the
> > > > ordinary muscles on. so choos a bodymodel version
> > > > names “_NoMuscles.any”. This model have each dof equipped
with
> > > moment
> > > > generating muscles, and you may read out the monments.
> > > >
> > > > The reason why we have a SacrumPelvis reaction is because
there
> > are
> > > no
> > > > muscles to carry this reaction.
> > > >
> > > > Please ask again if you have further questions.
> > > >
> > > > Best regards
> > > > S?en, AnyBody Support
> > > >
> > > >
> > > > — In anyscript@yahoogroups.com, “ninegu_sun” <ninegu_sun@>
> > wrote:
> > > > >
> > > > > Dear AnyBody Team,
> > > > >
> > > > > I’d like to get L5/S1 joint moments from an AnyBody
standing
> > > model.
> > > > > Joint reactions appear to give compressive forces, and
there
> > is
> > > > > Sacrumpelvis reaction folder.
> > > > > I though that sacrumpelvis reaction may be equivalent to
> L5/S1
> > > joint
> > > > > moments, yet values from sacrumpelvis reaction seem to be
too
> > > small.
> > > > >
> > > > > Is there a simple way to obtain L5/S1 joint moments?
> > > > >
> > > > > Sincerely,
> > > > > Sunwook
> > > > >
> > > >
> > >
> >
>