<t>Since there are several approaches which can calculate moment arms, I'm not positive which one OpenSim uses, but I believe it does it this way:<br/> <br/> Moment Arm = ( Change in length of muscle-tendon unit) / ( Change in joint angle)<br/> <br/> Note that the change in muscle-tendon length is a...

That error occurs when you have incorrectly specified the location or name of the file which you wish C3D server to open. Check that you have correctly entered the path to the file as well as the file name. Also make sure to include the extension (e.g. .c3d) of the file!

<r>Hi guys, <br/> <br/> I'm looking at some joint kinematics in rock climbing and comparing them to fiber length and seeing some oddities. Specifically, I'm looking at knee angle and vastus intermedius fiber length, which ought to have approximately a 1:1 relationship since the knee is 1 DOF in the ...

Is force-length the only relationship being considered, or does force-velocity also affect the calculation?

No, this is good. I just wanted to make sure I understand my data correctly.

Thanks guys!

Yes, with the plotter.

I think you're right about the 100% activation. I thought it was a sort of "max theoretical force production" but wanted a 3rd party verification.

Thanks!

<t>Hi all,<br/> <br/> I'm looking at fiber forces from inverse kinematics simulations where there is no dynamic or muscle activation data present. While passive fiber forces can easily be determined from force-length relationships from the muscle, I'm not sure what is meant by "active fiber force" i...

<t>Hi Tom, you and I briefly met at Stanford last year at the fall jamboree session. I am interested in using your interface to try and run forward dynamic simulations of rock climbing from Matlab using OpenSim's dynamics capabilities. I really appreciate that you've made this code available! Now on...

Good news! I installed the beta OSim 2.2 version and forces now all show up as long as I use the ground_force and ground_torque naming scheme. Thanks!

Has any modification been made to the coming version 2.2 release of OpenSim that would enable visualizing four forces simultaneously? I never could get it to work before.

Thanks!