Dynamic margins of stability during human walking in destabilizing environments

Patricia M. McAndrew Young, Jason M. Wilken, Jonathan B. Dingwell

Research output: Contribution to journalArticlepeer-review

163 Scopus citations


Understanding how humans maintain stability when walking, particularly when exposed to perturbations, is key to preventing falls. Here, we quantified how imposing continuous, pseudorandom anterior-posterior (AP) and mediolateral (ML) oscillations affected the control of dynamic walking stability. Twelve subjects completed five 3-minute walking trials in the Computer Assisted Rehabilitation ENvironment (CAREN) system under each of 5 conditions: no perturbation (NOP), AP platform (APP) or visual (APV) or ML platform (MLP) or visual (MLV) oscillations. We computed AP and ML margins of stability (MOS) for each trial. Mean MOS ml were consistently slightly larger during all perturbation conditions than during NOP (p≤0.038). Mean MOS ap for the APP, MLP and MLV oscillations were significantly smaller than during NOP (p<0.0005). Variability of both MOS ap and MOS ml was significantly greater during the MLP and MLV oscillations than during NOP (p<0.0005). We also directly quantified how the MOS on any given step affected the MOS on the following step using first-return plots. There were significant changes in step-to-step MOS ml dynamics between experimental conditions (p<0.0005). These changes suggested that subjects may have been trying to control foot placement, and consequently stability, during the perturbation conditions. Quantifying step-to-step changes in margins of dynamic stability may be more useful than mean MOS in assessing how individuals control walking stability.

Original languageEnglish (US)
Pages (from-to)1053-1059
Number of pages7
JournalJournal of Biomechanics
Issue number6
StatePublished - Apr 5 2012

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Orthopedics and Sports Medicine
  • Biomedical Engineering
  • Rehabilitation


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