PHYS THER

Vol. 82, No. 2, February 2002, pp. 138-147

Is Base of Support Greater in Unsteady Gait?

David E Krebs, Dov Goldvasser, Joyce D Lockert, Leslie G Portney and Kathleen M Gill-Body

DE Krebs, PT, PhD, is Professor, MGH Institute of Health Professions, 101 Merrimac St, Boston, MA 02114-4719 (USA) (KREBS@HELIX.MGH.HARVARD.EDU), and Director, Massachusetts General Hospital Biomotion Laboratory, Boston, Mass.
D Goldvasser, MScE, is Research Associate, Massachusetts General Hospital Biomotion Laboratory
JD Lockert, PT, MS, is in private practice at Advantage Sports Medicine, Woburn, Mass. She was a master's degree student at MGH Institute of Health Professions at the time of this study
LG Portney, PT, PhD, is Associate Professor, MGH Institute of Health Professions
KM Gill-Body, PT, MS, NCS, is Assistant Professor, MGH Institute of Health Professions, and Clinical Associate, Physical Therapy Services, Massachusetts General Hospital

Address all correspondence to Dr Krebs at the first address

Background and Purpose. We investigated dynamic interfoot distance (IFD) throughout the gait cycle in people with unsteady gait caused by vestibulopathy and in people without known neuromuscular pathology. We expected that the subjects with unsteady gait would use a greater IFD than subjects without neuromuscular pathology and that this IFD would be correlated with other measures of locomotor stability. Subjects and Methods. Simultaneous whole-body (11-segment) dynamic kinematic data were collected from 22 subjects with vestibulopathy and 22 subjects without known neuromuscular pathology who were matched for age, height, weight, and body mass index. Two trials each of the participants' gait at preferred speed and paced gait at 120 steps/min were analyzed with a repeated-measures design with multiple dependent variables. Quantitative data were analyzed descriptively and with inferential statistics. Results. Interfoot distance at preferred gait speed did not differentiate unsteady subjects with vestibulopathy from the comparison subjects. Paced gait IFD total range and IFD in single-limb support differed between groups, but IFD at heel-strike did not. However, IFD at heel-strike, the traditional measure of "base-of-support width," was correlated with measurements of whole-body center-of-gravity stability (r=.32–.55). Discussion and Conclusion. Gait at preferred speed permitted the unsteady subjects and the comparison subjects to select similar IFD values, but at the cost of slower gait in the unsteady subjects. When required to walk at a "normal" pace of 120 steps/min, subjects with vestibulopathy increased their IFD. These data suggest that wide-based gait alone cannot differentiate between subjects with and without balance impairments. Base of support and other whole-body kinematic variables are mechanical compensations of vestibulopathic instability. Further studies are needed to determine whether development of active control of these whole-body control variables can occur after vestibular rehabilitation.

Key Words: Gait • Interfoot distance • Kinematics • Stability • Vestibular dysfunction

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Copyright © 2002 by the American Physical Therapy Association.