This paper presents the analysis of a third-order linear differential equation representing the control of a muscle-tendon system, during quiet standing. The conditions of absolute stability and critical damping are analyzed. This study demonstrates that, for small oscillations, when the gravitational effect is modeled as a destabilizing negative stiffness and muscle-tendon stiffness is positive, the energy required to reach a critically damped state is very high. The high energy consumption is a consequence of a specific high threshold of muscle-tendon stiffness needed to achieve critical damping. An approximated graphical method confirms that during a hold and release paradigm intended to perturb quiet standing, the ankle response to fall recovery is proper of a third-order system. Furthermore, a direct estimation of the muscle and tendon parameters was obtained.

His dissertation presented a set of experimental and analytical validation techniques for human upper limb models. From 2004 to 2008 he was a visiting scholar and post-doctoral fellow at the Ashton Graybiel Spatial Orientation Lab at Brandeis University, under the supervision of Professors Paul DiZio and James R. Lackner. There, he worked on the mechanics of movement adaptation in non inertial environments as part of a NASA extramural funding program. He joined Northwestern University in 2008, working as a post-doc fellow at the Rehabilitation Institute of Chicago under the supervision of Professor Ferdinando (Sandro) Mussa-Ivaldi. Davide is currently Assistant Professor in the Mechanical Engineering department at Gannon University and director of the Biomedical Engineering Program. His main interest is to gain insights on the role of biomechanics in the neural control of movements, with applications to rehabilitation engineering.