static optimization for UE model

[Nithin Kurup]

Hi,

I am performing S.O on the mobl model after updating the muscles to Thelen2003 and adding reserve forces.

I can successfully run static optimization on a simple model having 4 muscles 2 deltoids and triceps and biceps long for an elbow flexion motion. But when verifying the force and muscle activation I noted that both triceps and biceps are getting activated together during the elbow flexion.( attached pic shows activation at 70 degree of flexion).

the time 0-1s represents elbow flexion from 15 degree to 90 degrees.

Hope someone can help me on this.

I can upload the files if it would help.

Thanks,

nithin

[jimmy d]

The long heads are bi-articular muscles and cause accelerations at other coordinates, not just the elbow_flexion coordinate.

[Nithin Kurup]

Thank you James for the reply. So it means that if I lock some the coordinates but enough to create flexion I should be able to produce results where biceps is more active and triceps with lesser activity.

thanks.

nithin

[Thomas Uchida]

if I lock some the coordinates but enough to create flexion I should be able to produce results where biceps is more active and triceps with lesser activity.

It isn't clear what you're trying to accomplish. If you're trying to create a simulation in which only the elbow flexors are active, then yes you could lock all coordinates except the elbow and track a flexion motion.

[Nithin Kurup]

Thank you for your reply.

Yes, I am trying to verify the elbow flexion extension muscles (major muscles). As there was some issues running the static optimization with the schutte muscle model with my original marker data, so I tried to update the muscle model to thelen and for verifying if the model works I tried to perform a simple elbow flexion, which resulted in both triceps and biceps getting activated together. So got into a confusion if I made some error editing the muscle model or some muscle path got altered.

Thanks for the help. Doubt is cleared.

nithin