The invention provides in silico models for determining the physiological function of human cells, including human skeletal muscle cells. The models include a data structure relating a plurality of Homo sapiens reactants to a plurality of Homo sapiens reactions, a constraint set for the plurality of Homo sapiens reactions, and commands for determining a distribution of flux through the reactions that is predictive of a Homo sapiens physiological function. A model of the invention can further include a gene database containing information characterizing the associated gene or genes. A regulated Homo sapiens reaction can be represented in a model of the invention by including a variable constraint for the regulated reaction. The invention further provides methods for making an in silico Homo sapiens model and methods for determining a Homo sapiens physiological function using a model of the invention.