Validating Activations Obtained from Static Optimization

[Luke Mattar]

Hi everyone,

I have developed a simple model of the glenohumeral joint consisting of the humerus, scapula, rotator cuff muscles and middle deltoid. The overall goal is to determine joint reaction force magnitude and direction in individuals with symptomatic rotator cuff tears. I account for the tear dimensions by decreasing the peak isometric force for the respective muscle-tendon unit.

My current workflow is IK-->SO-->JRF.

I have been able to confidently validate my results from IK, moment arms and my joint reaction force magnitudes based on the recommendations in the "Is My Model Good Enough" manuscript. However, our group did not collect EMG data during our experiments and I am having difficulty finding previous EMG literature in individuals with rotator cuff tears to validate the activations from SO. The only manuscripts I can find either do not report EMG during a large enough range of motion or do not report the actual curves.

If anyone has any suggestions or insight on how I can proceed in validating the activations it would be greatly appreciated. Thank you in advance for your time!