B Leg muscles’ force as a system of levers

  • B
  • Thread starter Thread starter KataruZ98
  • Start date Start date
  • Tags Tags
    Force System
AI Thread Summary
To break down the total force exerted by leg muscles into forces for each muscle group, one can use inverse dynamics to determine external joint torques from ground reaction forces. This process requires specifying an optimization criterion due to the problem being underdetermined. Muscle optimization techniques can then be applied to balance these external torques with the corresponding muscle forces. Software like OpenSim can facilitate this analysis, especially when simplifying the model to 2D with fewer muscles. Understanding these principles allows for a more accurate assessment of muscle force distribution in the leg.
KataruZ98
Messages
27
Reaction score
3
TL;DR Summary
How can I calculate the force exerted by each muscle group in a jump?
If I know a person has exerted total force F with their legs and I’m interested in breaking down said force in smaller forces exerted for each involved muscle group - how can I do it? With a basic level of understanding of human anatomy I can divide the leg as a series of levers but how can I specifically find force exerted by each lever?

EDIT: I’m aware “smaller” is not the correct word, but still..
 
Last edited:
Physics news on Phys.org
KataruZ98 said:
If I know a person has exerted total force F with their legs and I’m interested in breaking down said force in smaller forces exerted for each involved muscle group - how can I do it? With a basic level of understanding of human anatomy I can divide the leg as a series of levers but how can I specifically find force exerted by each lever?
Note that this is an underdetermined problem, so you need to specify an optimization criterion to get a unique solution. You use inverse-dynamics to get the external joint torques from the ground reaction force, and then muscle optimization to get the muscle forces that balance these external torques.

You can use software for that:
https://simtk.org/projects/opensim

If you simplify it to 2D and just a few muscles, then you might get something that you can solve by hand.
 
Last edited:
A.T. said:
Note that this is an undermined problem, so you need to specify an optimization criterion to get a unique solution. You use inverse-dynamics to get the external joint torques from the ground reaction force, and then muscle optimization to get the muscle forces that balance these external torques.

You can use software for that:
https://simtk.org/projects/opensim

If you simplify it to 2D and just a few muscles, then you might get something that you can solve by hand.
Ah, I see. Thank you very much, I’ll see what I’ll be able to do.
 
A.T. said:
undermined
I suspect that the correct word is underdetermined.

There are some nasty repetitions in there to entice the fingers to skip ahead in the sequence and no spell check to save you.
 
jbriggs444 said:
I suspect that the correct word is underdetermined.
Yes, thanks. Fixed it.
 
Thread 'Question about pressure of a liquid'
I am looking at pressure in liquids and I am testing my idea. The vertical tube is 100m, the contraption is filled with water. The vertical tube is very thin(maybe 1mm^2 cross section). The area of the base is ~100m^2. Will he top half be launched in the air if suddenly it cracked?- assuming its light enough. I want to test my idea that if I had a thin long ruber tube that I lifted up, then the pressure at "red lines" will be high and that the $force = pressure * area$ would be massive...
I feel it should be solvable we just need to find a perfect pattern, and there will be a general pattern since the forces acting are based on a single function, so..... you can't actually say it is unsolvable right? Cause imaging 3 bodies actually existed somwhere in this universe then nature isn't gonna wait till we predict it! And yea I have checked in many places that tiny changes cause large changes so it becomes chaos........ but still I just can't accept that it is impossible to solve...
Back
Top