Simplifying the Glasglow-Maastricht foot model

Dear AnyBody community

We want to calculate the hindfoot kinematics during gait trials. We found that in AnyBody two foot models exist namely the basic model with only two joints (ankle and subtalar joint) and the extensive Glasgow-Maastricht foot model. The former is too simple for our application. However, the latter is too detailed as we are not interested in all the included joints (for example the interphalangeal and metatarsophalangeal joints) and including all the skin markers is labour-intensive.
Therefore, we would like to adjust the Glasgow-Maastricht foot model by excluding/fixing the joints where we are not interested in. However, we are not sure whether this would affect the output of the other joints (which are under investigation) in the foot model. The output of the Glasgow-Maastricht foot model is compared with existing literature (as validation). Can we assume that the model remains valid (for the kinematics in the hindfoot) if we decrease the degrees of freedom by combining multiple bones of the forefoot (and midfoot) into one segment?

Is there anyone who has already encountered a similar problem/ dealt with something similar? Any suggestion to address the above would be greatly appreciated.

With kind regards
Kate Duquesne

Hi @kateduquesne

If you are going to modify the GM-foot model I would like to point you to the newest version on it which you can find here on github.

It is safe to assume that fixating or excluding some of the joints will affect the results you obtain.
There are several closed chains in the foot model which make it hard to model.
You can therefore not assume it as valid when altering the model in the way you want.

Others have done similar things as you intend.
Here is a article where they reduced the number of segments to 5.
Unfortunately we do not have the model so you will have to reach out to the authors yourself.

Best regards,
Bjørn
AnyBody Technology

Dear Bjorn

Thank you for the quick reply and for including the article. Your response was very helpful!

Best regards
Kate Duquesne

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