JOHN is a computer model designed to study the interaction of the human skeletal structure during postural changes. Muscles can also be added to the simulation, and muscular/skeletal interaction can be studied.
The functionality of the MSU JOHN models have been incorporated into automotive package software called RAMSIS, developed by Human Solutions. The deformed body contours to various sized individuals was studied. This ability was incorporated into the RAMSIS models. Also, a special module was developed by Human Solutions that allowed the RAMSIS model to move like JOHN, treating the thorax and pelvis as rigid bodies and connecting them with a single two-joint link.