The present invention relates to a method and corresponding system for modeling a musculo-skeletal system. An embodiment of the method of the invention begins by scaling and positioning a musculo-skeletal model to correspond with motion capture data of a subject. Next, kinematically consistent motion data is generated from the motion capture data and then an inverse dynamic analysis of the musculo-skeletal model is performed using the generated kinematically consistent motion data, such that at least one analysis result is generated. The musculo-skeletal model is then updated to correspond with the at least one analysis result of the inverse dynamic analysis. Finally, the muscle activation of the updated musculo-skeletal model is optimized by determining at least one muscle force using the updated musculo-skeletal model, and by further updating the updated musculo-skeletal model to correspond with the determined at least one muscle force.