Human Sway on a Balance Platform

for balance recovery are used. Postural strategies are automatic stable
muscular patterns. Such a mechanism reduces the degrees of freedom
number, simplifies, speeds up the posture adjustment, and minimizes
energy expenditure. They relate to the existence of some motor
coordination sets and describe three mobility strategies: ankle, hip,
and step strategy. The hip strategy occurs when interference is greater
or the use of the ankle strategy is impossible, for example, due to the
delay of the postural information cycle. From a dynamical systems
point of view, a human attempting to balance upright on an unstable
balance board represents the coupling of two dynamical systems, the
human balance system with neuromuscular feedback supported on
the balance board (an inverted pendulum). The coupling of these two
dynamical systems, with time delay and nonlinearities, creates an
ideal setting for the emergence of complex postural behaviour and
unanticipated interactions between the individual, task, and the
external dynamical system. The article presents an analysis of the
pendulums concerning the issue of maintaining balance by man.