Assessment of walking stability by Lyapunov exponent estimation

Y. Ohtaki, Y. Iijima, M. Arif, A. Suzuki, R. Nagatomi, H. Inooka

Research output: Contribution to journalConference articlepeer-review

2 Citations (Scopus)


This paper presents a unique technique to estimate walking stability utilizing a small and light-weight portable instrument. Lyapunov exponent estimation, a method of nonlinear time series analysis, was applied to quantify the dynamic stability of body sway during walking as measured by accelerometry. Fourteen young and twenty-one elderly subjects participated this study. Lyapunov exponent of the elderly subjects tended to be higher suggesting lower stability as compared to the younger subjects. Moreover, the elderly subjects suffering knee pain or frequent history of fall presented higher value as compared to those having exercise habit. The results suggest that Lyapunov exponent estimation of walking stability is useful to assess locomotive ability.

Original languageEnglish
Pages (from-to)2475-2476
Number of pages2
JournalAnnual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
Publication statusPublished - 2002
EventProceedings of the 2002 IEEE Engineering in Medicine and Biology 24th Annual Conference and the 2002 Fall Meeting of the Biomedical Engineering Society (BMES / EMBS) - Houston, TX, United States
Duration: 2002 Oct 232002 Oct 26


  • Accelerometry
  • Locomotion
  • Nonlinear time series analysis
  • Stability


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