Reason for no forces in triceps

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1

Hi,
I am using FreePosture Static for this simulation.

I was wondering why there is no force in the Triceps muscles when I hold my elbow in 90-degree flexion and run the simulation for that static posture.

Thank you.

Regards,
Kamal

2

Hi Kamal,

When the elbow is flexed 90 deg gravity will pull downwards and triceps does not need to be active.
To see triceps action try to add a force pulling the arm forward or upward.

Best regards
Søren

3

Hi Soren,
Thank you for the reply.
I understand your point.
While I notice that there is no force in the contractile element (Fm), there are some small forces in the range of 2.3 N in the passive elements of each triceps muscle. Do I need to consider those forces, or is it due to incorrect calibration of the TendonLengthCalibration?

Thank you

Best
Kamal

4

Hi Kamal,

I am not 100 % sure which position the arm is calibrated in, so it is likely that there are a bit of passive force in that position.

Best regards
Søren

5

Hi,
I think those are calibrated in multiple positions like abduction, flexion of arm and 65 degree elbow flexion. So do I need to calibrate for 90 degree flexion only?

Thank you.

Kamal

6

Hi Kamal,

The positions for calibration has been chosen when creating the arm model, it is not intended to use different calibration positions for different tasks.

Why is it important that you get exactly zero passive force for triceps in that position?

If you want to have zero at specific angle, you would need to ensure that the calibration study working on triceps would be using this angle.

Best regards
Søren

7

Hi,
Thank you for the clarification. I got my answer.
Once again, thank you for the support.

Regards,
Kamal

8

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