Can Tai Chi training impact fractal stride time dynamics, an index of gait health, in older adults? Cross-sectional and randomized trial studies.


Author: Gow BJ1,2, Hausdorff JM3, Manor B4, Lipsitz LA4,5, Macklin EA6, Bonato P7,8, Novak V4,9, Peng CK2, Ahn AC2,10, Wayne PM1

Affiliation: <sup>1</sup>Osher Center for Integrative Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.

<sup>2</sup>Division of Interdisciplinary Medicine and Biotechnology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America.

<sup>3</sup>Center for the Study of Movement, Cognition, and Mobility, Neurological Institute, Tel Aviv Sourasky Medical Center, Sagol School of Neuroscience and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.

<sup>4</sup>Division of Gerontology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America.

<sup>5</sup>Institute for Aging Research, Hebrew SeniorLife, Roslindale, Massachusetts, United States of America.

<sup>6</sup>Biostatistics Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, United States of America.

<sup>7</sup>Motion Analysis Laboratory, Spaulding Rehabilitation Hospital, and the Department of Physical Medicine and Rehabilitation, Harvard Medical School, Boston, Massachusetts, United States of America.

<sup>8</sup>Harvard-MIT Division of Health Sciences and Technology, Cambridge, Massachusetts, United States of America.

<sup>9</sup>Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, United States of America.

<sup>10</sup>Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America.
Conference/Journal: PLoS One.
Date published: 2017 Oct 11
Other:
 Volume ID: 12   ,  Issue ID: 10   ,  Pages: e0186212   ,  Special Notes: doi: 10.1371/journal.pone.0186212. eCollection  2017.   ,  Word Count: 285  
    PURPOSE: To determine if Tai Chi (TC) has an impact on long-range correlations and fractal-like scaling in gait stride time dynamics, previously shown to be associated with aging, neurodegenerative disease, and fall risk.



METHODS: Using Detrended Fluctuation Analysis (DFA), this study evaluated the impact of TC mind-body exercise training on stride time dynamics assessed during 10 minute bouts of overground walking. A hybrid study design investigated long-term effects of TC via a cross-sectional comparison of 27 TC experts (24.5 ± 11.8 yrs experience) and 60 age- and gender matched TC-naïve older adults (50-70 yrs). Shorter-term effects of TC were assessed by randomly allocating TC-naïve participants to either 6 months of TC training or to a waitlist control. The alpha (α) long-range scaling coefficient derived from DFA and gait speed were evaluated as outcomes.



RESULTS: Cross-sectional comparisons using confounder adjusted linear models suggest that TC experts exhibited significantly greater long-range scaling of gait stride time dynamics compared with TC-naïve adults. Longitudinal random-slopes with shared baseline models accounting for multiple confounders suggest that the effects of shorter-term TC training on gait dynamics were not statistically significant, but trended in the same direction as longer-term effects although effect sizes were very small. In contrast, gait speed was unaffected in both cross-sectional and longitudinal comparisons.



CONCLUSION: These preliminary findings suggest that fractal-like measures of gait health may be sufficiently precise to capture the positive effects of exercise in the form of Tai Chi, thus warranting further investigation. These results motivate larger and longer-duration trials, in both healthy and health-challenged populations, to further evaluate the potential of Tai Chi to restore age-related declines in gait dynamics.



TRIAL REGISTRATION: The randomized trial component of this study was registered at ClinicalTrials.gov (NCT01340365).



PMID: 29020106  DOI: 10.1371/journal.pone.0186212