Dynamic evolution of equivalent von Mises stress on a bilateral fusion assembly. The assembly shown here without the instrumented spine level (L5-L4) is loaded in «slow motion» to what corresponds to the stance phase of a mild running scenario (0.2s). The applied force consideres the vertical force component of the ground reaction force as registered by a force plate. A detailed description of model on which this scenario was preformed, may be found in the Journal of Clinical Biomechanics 28 (9-10) (2013) 949-955.