Instability

In dynamical systems instability means that some of the outputs or internal states increase with time, without bounds.

Mechanical instability includes insufficient stabilizing structures and mobility that exceed the physiological limits.

Instability leads to an increase in postural sway, the measurement of the time and distance a subject spends away from an ideal center of pressure.

Investigators have theorized that if injuries to joints cause deafferentation, the interruption of sensory nerve fibers, and functional instability, then a subject's postural sway should be altered.

[7] Joint stability can be enhanced by the use of an external support system, like a brace, to alter body mechanics.