Nonlinear Dynamics and Bifurcations in Postural Control on Rigid Surfaces and Rotational Balance Boards

A balance board is an unstable platform which is currently used for training and rehabilitation to stabilize an individual’s upright posture. Models that examine how individuals remain upright while standing on an unstable surface are therefore needed to understand the mechanisms behind balance improvements. Most research in this area has focused on the fluctuations in posture about a static upright equilibrium using single-degree-of-freedom (1-DOF) inverted pendulum models [1–2]. While conceptually simple, these models nonetheless capture the stochastic, nonlinear and multiple timescale behavior of the fluctuations that are known to occur in human posture [1–3].