Simulated Muscle Weakness
Posted: Tue May 03, 2022 10:51 am
Hi everyone,
I want to simulate hip flexor weakness during gait using Moco and I have marker data and EMG signals to use as input. I also have MVIC force production data from hip muscles.
I am basing the feasibility of my design off of the OpenSim Moco publication, specifically the section "Tracking a walking motion with normal and weakened muscles"
It states "We next weakened the ankle dorsiflexor muscles [tibialis anterior, extensor digitorum longus, and extensor hallucis longus] by reducing max isometric forces by 95% and solved the tracking problem again [using the "normal" solution for the initial guess]." "...We used the original cost terms that penalized squared controls and tracking error."
Has anyone applied such practices and have Matlab code they would share so I can visualize more details about how this is accomplished? I plan to track both marker data and EMG in the "normal" solution, but not use the EMG in the weakness conditions as this is what I want to alter. Is it appropriate to input the MVIC force values at all or does OpenSim compute these?
Has anyone applied this in a MocoStudy predictive simulation? Wouldn't a predictive solution technically be the most robust way to analyze?
Thanks in advance, I am trying my best with the documentation available but figured experience from someone who has done it might help me get over my hurdles.
I want to simulate hip flexor weakness during gait using Moco and I have marker data and EMG signals to use as input. I also have MVIC force production data from hip muscles.
I am basing the feasibility of my design off of the OpenSim Moco publication, specifically the section "Tracking a walking motion with normal and weakened muscles"
It states "We next weakened the ankle dorsiflexor muscles [tibialis anterior, extensor digitorum longus, and extensor hallucis longus] by reducing max isometric forces by 95% and solved the tracking problem again [using the "normal" solution for the initial guess]." "...We used the original cost terms that penalized squared controls and tracking error."
Has anyone applied such practices and have Matlab code they would share so I can visualize more details about how this is accomplished? I plan to track both marker data and EMG in the "normal" solution, but not use the EMG in the weakness conditions as this is what I want to alter. Is it appropriate to input the MVIC force values at all or does OpenSim compute these?
Has anyone applied this in a MocoStudy predictive simulation? Wouldn't a predictive solution technically be the most robust way to analyze?
Thanks in advance, I am trying my best with the documentation available but figured experience from someone who has done it might help me get over my hurdles.