All of our predictive models are validated with motion capture, and much of this validation work and the methods by which it is done has been published. See the following links to download those publications:
https://www.santoshuman.com/Presentations/Validation%20MoCap%20%26%20Pos%20Pubs.zip
https://www.santoshuman.com/Presentations/Moven_Validation_FINAL.pdf
https://www.santoshuman.com/Presentations/Mocap_Vib_IJIE_Paper_08.pdf
With regards to studies that have used Santos technologies to drive applications designed for muscle force simulations like OpenSim, download this zipped file.