modifying model

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1

Hello

I would like to modify the GaitLowerExtremity model by changing the femoral offset. How would I do this? I have found something for hip offset but was wondering if this was the same thing?

2

Hi Ammar,

Please have a look into another thread. You could use the same code.

Regards,
Pavel

3

Hi

I added the code that you recommended into gaitlowerextremity in AMMR V1.5 and it processed fine. However I still get the same output for the joint reaction forces at the hip when I change the offset. I was wondering what I was doing wrong?

4

Hi,

I would recommend you to upload your model in the debug section:
http://forum.anyscript.org/forumdisplay.php?f=21

Best regards,
Moonki

5

Thank you for your replies.

I will upload the model shortly into the debug section.

For the time being I have another query. I have been trying to simulate patients with a leg length difference by increasing the thigh length of one of the legs. However I am unsure whether by increasing the thigh length the muscles are also scaled according to the new thigh length in size or if the size remains the same with the muscles just being stretched. If the muscles are being scaled as well, how would I modify the model so that the muscles are not scaled but are just stretched as this is what I would like to achieve.

Regards

Ammar

6

Hi Ammar,

This is called muscle length calibration. You can read more in the tutorials. What you need to do is to calibrate the muscles in the original state and then apply you shortening/lengthening.

You could run a sequence of operations as follows:
[ol]
[li] Calibration[/li][li] Shortening/Lengthening [/li][li] Inverse Dynamics analysis.[/li][/ol]

Best regards,
Pavel

7

Hi

I am confused with regards to calibration. When choosing 3E muscle elements and running the inverse dynamics I get for example the following

" GemellusSuperior1 : Muscle calibration : The tendon/fiber length of the muscle was calibrated according to the executed muscle calibration and the muscle model properties have been updated"

So does this mean that the muscle has been calibrated? T thought that the calibration must be carried out before the inverse dynamics?

8

Hi,

you can always change parameters before doing the inverse dynamics but of course I is possible that something goes wrong, just try it.

Regards,
Patrick