Hi All,

Indeed, I am using SIMM (which I guess it is just similar to openSIM). My question is the option which calculate "System Energy". Do anybody knows, how exactly SIMM, or openSIM do calculate total system energy? Is it simply by indirectly calculating total muscle activations? (And thus measured by Voltage?) I have look at the SIMM user document, but it does not explain it well.

Thank you in advance for the help

## System Energy

### Re: System Energy

A brief description of how OpenSim calculates Metabolics is described on the confluence example page....http://simtk-confluence.stanford.edu:80 ... bolic+Cost

"The metabolics calculators in OpenSim can calculate the rate or total amount of energy consumption for each muscle in the model, and for the whole body. The models of metabolics from Umberger et al. (2003) and (2010) account for the effect of muscle mass, the ratio of fast- and slow-twitch fibers in the muscle, and the lengthening/shortening velocity. The model you've been working with in Sections I and II above includes a set of metabolic probes to calculate the energy consumed by all the muscles in the model, as well as each individual muscle on its own. Read more about the metabolic probes on their doxygen page."

"The metabolics calculators in OpenSim can calculate the rate or total amount of energy consumption for each muscle in the model, and for the whole body. The models of metabolics from Umberger et al. (2003) and (2010) account for the effect of muscle mass, the ratio of fast- and slow-twitch fibers in the muscle, and the lengthening/shortening velocity. The model you've been working with in Sections I and II above includes a set of metabolic probes to calculate the energy consumed by all the muscles in the model, as well as each individual muscle on its own. Read more about the metabolic probes on their doxygen page."