How Good is Good Enough? Lessons in Musculoskeletal Model Validation With the Anybody Modeling System

In the last two decades a steady evolution has taken place in the realm of musculoskeletal simulation, which is now taking an increasingly central role in guiding ergonomics evaluations, influencing medical device design, and informing clinical decisions. Musculoskeletal simulation holds tremendous promise to help bring safer, more innovative products to market more quickly and to drive optimized, patient-specific care. But, to effectively deliver on these challenging goals, both the software and the models created from it must meet high expectations for verification and validation so that critical choices influenced by simulation can be made with confidence. Verification is the job of the software developer, but due to the breadth of modeling applications, the task of validation falls to the user. Rigorous model validation is time consuming and often technically difficult. And so, the question arises, in the context of both verification and validation, “How good is good enough?” The goal of this paper is to offer a response to that question. The discussion will be complemented by relevant validation examples from the open literature pertaining to one commercial musculoskeletal simulation software, the AnyBody Modeling System (AMS).