Sports Medicine

, Volume 35, Issue 11, pp 935–950

A Nonlinear Dynamic Approach for Evaluating Postural Control

New Directions for the Management of Sport-Related Cerebral Concussion


    • Geriatric Research, Education and Clinical Center, Department of Veterans Affairs Medical Center
    • Department of Physical and Occupational TherapyDuke University Medical Center
  • Kevin M. Guskiewicz
    • Department of Exercise and Sport ScienceUniversity of North Carolina
  • Nicholas Stergiou
    • HPER Biomechanics LaboratoryUniversity of Nebraska at Omaha
Review Article

DOI: 10.2165/00007256-200535110-00002

Cite this article as:
Cavanaugh, J.T., Guskiewicz, K.M. & Stergiou, N. Sports Med (2005) 35: 935. doi:10.2165/00007256-200535110-00002


Recent research suggests that traditional biomechanical models of postural stability do not fully characterise the nonlinear properties of postural control. In sports medicine, this limitation is manifest in the postural steadiness assessment approach, which may not be sufficient for detecting the presence of subtle physiological change after injury. The limitation is especially relevant given that return-to-play decisions are being made based on assessment results. This update first reviews the theoretical foundation and limitations of the traditional postural stability paradigm. It then offers, using the clinical example of athletes recovering from cerebral concussion, an alternative theoretical proposition for measuring changes in postural control by applying a nonlinear dynamic measure known as ‘approximate entropy’. Approximate entropy shows promise as a valuable means of detecting previously unrecognised, subtle physiological changes after concussion. It is recommended as an important supplemental assessment tool for determining an athlete’s readiness to resume competitive activity.

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© Adis Data Information BV 2005