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Kazanski Et Al 2022

Rethinking margin of stability: Incorporating step-to-step regulation to resolve the paradox

Tags: #locomotion #gait #margin_of_stability

Related: [[The Condition for Dynamic Stability - Hof Et Al 2005]] [[Measures to Determine Dynamic Balance - Niiler 2015]]

Key Definitions

Key Takeaways

  1. Average margin of stability values lead to paradoxical results in some key cases. People with known gait problems often have a larger margin of stability than those without, even though a larger margin of stability is generally associated with better balance.
    1. This is due to the process of averaging removing important step-to-step dynamics
  2. The margin of stability condition is met when the extrapolated center of mass falls within the boundaries of the base of support for that step. But because it is evaluated at each step, it cannot evaluate step to step transitions and must be recalculated at each step.
  3. Because the COM moves throughout the body, or even outside the body, it is unlikely that humans are aware of the location of their COM or are able to actuate it.
    1. This seems relatively suspicious, given all the cases where we're forced to move about our COM, or move our COM, and are able to do so.
    2. Claim is that instead of altering our COM, we indirectly adjust our COM by changing other processes like foot placement.
    3. Hypothesis is that regulations of mediolateral foot placement explain mediolateral COM dynamics.

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