This project holds three different OpenSim-based musculoskeletal model of the human lumbar spine. Please refer to the ReadMeFirst document for more detail on the documents/model downloads available. Briefly, the models differ in their complexity with the simplest (Lumbar_C_4) featuring only 4 muscle fascicles, and no wrapping surfaces, while the more complex ones have 210 (Lumbar_C_210) and 238 (Lumbar_C_238) muscle fascicles respectively as well as wrapping surfaces for the erector spinae muscle fibers. The joints in all three models are modeled as ball and socket joints with three rotational degrees-of-freedom constrained to be a fraction of the net lumbar motion. In order to respect the time and effort put in by the original developers please carefully read accompanying publications and cite appropriate references in future work. Good luck and Have Fun!

Briefly explains how to edit the .vtp files available in the OpenSim "Geometry" folder if you don't have a .vtp file editor. Useful in, e.g., redefining the origin of the .vtp file to coincide with the center of mass of the body. - The pdf explains how to do things on your own. - matlabCode is the Matlab Code alone, assuming you've copied and pasted the appropriate portion of the .vtp file into corresponding .txt files - Tryout Example contains the Matlab Code, input and output .txt files, and a folder containing the lumbar .vtp files with origins set to the geometric centers of the bodies. The easiest way to do things is to read through the .pdf explanation first and really understand it. That'll help you decide if you need to download the Matlab Code/Tryout Example folder.

A set of .vtp Geometry files to be used to model the spine. These are modified versions of those available in OpenSim's Geometry folder, but the origins have been moved to the center of the vertebras. Two sets are featured. One consists of the Sacrum through Lumbar 1 while the second consists of the Lumbar 5 through Thoracic 1 .vtp giles.