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SO and EMG results differ.

Posted: Sat Sep 02, 2023 2:40 am
by zakky
Hello, every one.

I am currently investigating muscle activity during bicycle use.
As a problem, the results calculated by SO compared to actual EMG are different.
This is particularly noticeable in the gastrocnemius muscle, which is a bi-articular muscle near the knee joint. Floor reaction forces are given.
The images show the results of calculations in Opensim in the gastrocnemius and biceps femoris muscles at the same time (left) and the actual EMG (right). Thus, the error is greater in the gastrocnemius muscle.
Any advice on how to solve this problem?
Image
Best regards.

Re: SO and EMG results differ.

Posted: Tue Sep 05, 2023 12:02 am
by kernalnet
Hi, by using a muscle volume-weighted cost function and/or a power of 3 or 4, you may get better results.

viewtopic.php?f=91&t=14556&p=42087&star ... d5d#p42064
https://doi.org/10.1016/j.gaitpost.2019.08.019

There are also some tools for incorporating EMG in SO: CEINMS, EMG Optimization Tool, Matlab Static Optimization

I'm interested in this topic and wondering if you inform us of your findings.

Thank you,
Mohammadreza

Re: SO and EMG results differ.

Posted: Sun Sep 10, 2023 2:24 am
by zakky
Thank you for your reply.

I would like to try the suggested methods.
I will report back if there is any improvement.

Best regards.