Model-Based Investigation of Ankle Stiffness Control Versus Active Feedback Control During Quiet Standing

The mechanisms involved in generating corrective torques to maintain balance during human upright stance have been attributed to passive control (i.e. intrinsic properties of muscles and tendons, such as the intrinsic stiffness and viscoelasticity of muscles) and active control (i.e. neurally-mediated sensory-based feedback control) [1–3]. While there continues to be some debate over the roles of active versus passive mechanisms in maintaining balance, especially during quiet (unperturbed) standing [4–6], the general consensus is that both mechanisms contribute to postural control [3]. However, active mechanisms have been shown to play a more dominant role in maintaining upright stance, particularly during perturbed conditions [7, 8].© 2011 ASME