Components of the equations in the Forward Dynamics problem

[Humans Clinic]

I am not an expert in biomechanics, please pardon me if you find my question too basic, or if it doesn't make sense. Actually I am kind of using OpenSim to learn biomechanics.

In the documentation on the forward problem on "How Forward Dynamics Works", I see what theories and equations the software uses to predict/simulate the kinematics of a human model from certain inputs. Newton's Second Law is clearly used, and has widespread coverage in all physics, classical mechanics, and even biomechanics literature. Other components of the equations are less widely known, and I'd like to learn more about them.

In particular, there are many functions, and it is not shown what the actual expressions are that these functions represent. How do I know what they are? I especially need to know about:
Muscle contraction dynamics, where l' = V(a,l,q,q')
Muscle activation dynamics, where a' = A(a,x)

Also, how can I find theoretical literature on why the functions are valid?

[Axel Koussou]

Hi,

This article : https://www.mov-sport-sciences.org/arti ... 20026.html and those to which it refers might give you some informations.

Hope this helps,

Regards