Boundaries are defined limits or borders that indicate lines that should not be crossed. Venture beyond a boundary and negative consequences likely wait. Examples of boundaries include lines on a road and fences around a yard. Respective examples of negative consequences include oncoming cars and angry dogs.
Balance is the capability to remain steady on one’s feet. Steadiness is the ability to stand or move without hesitation, holding, touching, slowness of movement, or presence of obvious balance reactions (ankle, hip, knee or stepping). Conversely, a loss of balance results in reaching, grabbing, swaying, stepping, etc. Balance is important for safely completing activities of daily living and navigating around our homes and communities.
A balance boundary is a limit at which, if crossed, steadiness can no longer be maintained. Unlike a fence or sign, balance boundaries cannot be seen (until balance is lost), but they are easily felt. Reach, shift, or move within the boundary and balance, and steadiness is maintained. However, move beyond the boundary, balance is lost, and feelings of unsteadiness can overwhelm. Once beyond the balance boundary, if self-correction is not effective, or if help/external support is not immediately available, then a fall may ensue.
In order to help prevent falls, balance boundaries need to be established. Boundaries may be reach distances (high, low, behind midline, etc.), step heights, step lengths, weight-shift excursions, etc. If a patient knows their boundaries of stability, unexpected losses of balance can be avoided. Because balance changes drastically following injuries and surgeries (stroke, brain injury, hip ORIF, etc.), as therapists, we need to help patients establish and respect their current balance boundaries. Additionally, we also need encourage and train patient to improve their balance expand their limits of stability.
NOTE: Picture shows balance boundary of step height with ADL Quadrant Hurdle.