Estimating muscle power from static optimization results

[Maria Isabel Orselli]

Hi all,

I'm trying to estimate muscle power using the results I obtained from a static optimization analysis and I was planning to use muscle analysis in the Analyze Tool. Is there any way to use this with static optimization results?

It seems to me that if it was possible, as the Static Optimization consider tendons rigid and no paralel elasticity, I would have to indicate somewhere that I wan't to use this approach and also to indicate were forces files are. Where I can do this?

If its not possible should I use the results of MuscleAnalysis_Length.sto to estimate the contraction velocity of each muscles? Is it possible to obtain the muscle moment arms (my files came empty)?

thanks,
Bel

[jimmy d]

Hi Bel,

You do have acouple options here. As StaticOP gives you muscle forces and velocities you could calculate manually.

Otherwise you can use the analysis tool. The instantaneous actuator states (force and velocity) are read and analysed (Power in watts). You would have to take your staticOp results alittle further though since the Analyze Tool has the same inputs and outputs as the Forward Dynamics Tool.

You can find a description of the analysis tool here:
"http://simtk-confluence.stanford.edu:80 ... h+Analyses"

let us know how it goes,
-james

[Maria Isabel Orselli]

Hi James,

thanks I'll work on those options, but i still have a question. I don't know if I understand right, when you say:

You do have acouple options here. As StaticOP gives you muscle forces and velocities you could calculate manually.

are you refering to the muscles contraction velocitie ?
If so, can you indicate how I get them. In my results I just have the activation and the forces.

Thanks
Bel