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responses of young and old adults to postural disturbances: kinemat-
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7. Rogers MW, Hain TC, Hanke TA, Janssen I. Stimulus parameters and
inertial load: effects on the incidence of protective stepping responses.
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8. Maki BE, McIlroy WE. The role of limb movements in maintaining
upright stance: the “change-in-support” strategy. Phys Ther. 1997;77:
488–507.
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NB. Age differences in using a rapid step to regain balance during a
forward fall. J Gerontol Med Sci. 1997;52A:M8–M13.
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namic predictions of protective stepping following waist-pull perturbations
in young and older adults. J Biomech. 1998;31:1111–1118.
11. Hsiao ET, Robinovitch SN. Biomechanical influences on balance re-
covery by stepping. J Biomech. 1999;32:1099–1106.
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ing leg flexion movements in man. Exp Brain Res. 1990;81:398–401.
13. Mouchnino L, Aurenty R, Massion J, Pedotti A. Coordination between
equilibrium and head-trunk orientation during leg movement: a new
strategy built up by training. J Neurophysiol. 1992;67:1587–1598.
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stepping. Exp Brain Res. 1997;115:345–356.
Figure 5. Group mean values ꢀ 1 SEM for medio-lateral (M-L)
foot placement at the instant of the first-step foot contact during for-
ward-induced stepping at small (P3), medium (P4), and large (P5)
waist pulls. Positive values indicate motion toward the mid-sagittal
line of the body. *Indicates a significant difference (p ꢂ .001) be-
15. Rogers MW. Disorders of posture, balance, and gait in Parkinson’s
disease. In: Studenski S, ed. Geriatric Medicine Clinics: Gait and Bal-
ance Disorders. Philadelphia, PA: WB Saunders; 1996;4:825–845.
16. McIlroy WE, Maki BE. The control of lateral stability during rapid
stepping reactions evoked by antero-posterior perturbation: does antic-
ipatory control play a role? Gait Posture. 1999;9:190–198.
17. Maki BE, Holliday PJ, Topper AK. A prospective study of postural
balance and risk of falling in an ambulatory and independent elderly
population. J Gerontol Med Sci. 1994;49:M72–M84.
18. Lord SR, Rogers MW, Howland A, Fitzpatrick R. Lateral stability,
sensorimotor function and falls in older people. J Am Geriatr Soc.
1999;47:1077–1081.
19. Nevitt M, Cummings SR. Type of fall and risk of hip and wrist frac-
tures: the study of osteoporotic fractures. J Am Geriatr Soc. 1993;41:
1226–1234.
20. Hayes WC, Myers ER, Morris JN, Gerhart TN, Yett HS, Lipsitz LA.
Impact near the hip dominates fracture risk in elderly nursing home
residents who fall. Calcif Tissue Int. 1993;52:192–198.
21. Cumming RG, Klineberg RJ. Fall frequency and characteristics and
the risk of hip fractures. J Am Geriatr Soc. 1994;42:774–778.
22. McIlroy WE, Maki BE. Age-related changes in compensatory step-
ping in response to unpredictable perturbations. J Gerontol Med Sci.
1996;51A:M289–M296.
tween fallers versus nonfallers and young adults. ꢀ P3; ꢁ P4;
P5.
als who reported a recent history of falling moved more lat-
erally more quickly at the completion of the first step than
younger and older adult nonfallers. This difference in lateral
stepping behavior was not attributable to changes in antici-
patory postural mechanisms but appeared to involve fac-
tors associated with the subsequent compensatory stepping
movement and/or differences in response strategies related
to prior planning. The results highlight the association be-
tween falling in older people and particular changes in con-
trolling lateral body motion during dynamic balance recov-
ery through stepping. Our ongoing studies are seeking to
further identify the impairments contributing to lateral bal-
ance dysfunction to specify rehabilitation interventions for
minimizing the incidence of falls among older individuals.
Acknowledgments
23. Maki BE, Edmondstone MA, McIlroy WE. Age-related differences in
laterally directed compensatory stepping. J Gerontol Med Sci. 2000;
55A:M270–M277.
24. Tinetti ME, Speechly M, Ginter SF. Risk factors for falls among elderly
persons living in the community. N Engl J Med. 1988;319:1701–1707.
25. Winter DA. Biomechanics and Motor Control of Human Gait. Water-
loo, Ontario: University of Ontario Press; 1987.
26. Pidcoe PE, Rogers MW. A closed-loop stepper motor waist-pull system
for inducing protective stepping in humans. J Biomech. 1998;31:377–381.
27. Luchies CW, Wallace D, Pazdur R, Young S, DeYoung AJ. Effects of
age on balance assessment using voluntary and involuntary step tasks.
J Gerontol Med Sci. 1999;54A:M140–M144.
28. Rogers MW, Kukulka CG, Brunt D, Cain TD, Hanke TA. Influence of
stimulus cue on the initiation of stepping in young and older adults.
Arch Phys Med Rehabil. 2001;82:619–624.
29. Winter DA. A.B.C. of Balance during Standing and Walking. Water-
loo, Ontario: Graphic Services, University of Waterloo; 1995.
30. MacKinnon CD, Winter DA. Control of whole body balance in the
frontal plane during human walking. J Biomech. 1993;26:633–644.
31. Day BL, Severac Cauquil A, Bartolomei L, Pastor MA, Lyon IN. Hu-
man body-segment tilts induced by galvanic stimulation: a vestibularly
driven balance protection mechanism. J Physiol. 1997;500:661–672.
This work was supported by National Institutes of Health Grants K01
AG00581 and R01 AG16780 to MWR.
We thank J.D. Brooke, M.J. Poval, and M. Simoneau for comments on
an earlier draft of the article. The technical assistance of F. Gao, Y. Zhang,
and S. Redman is gratefully acknowledged.
Portions of this work were presented at the Third North American Congress
on Biomechanics, Waterloo, Ontario, Canada, 1998, and the International Soci-
ety of Biomechanics XVIIth Congress, Calgary, Alberta, Canada, 1999.
Address correspondence to Mark W. Rogers, PhD, PT, Department of
Physical Therapy and Human Movement Sciences, Northwestern Univer-
sity Medical School, 645 North Michigan Avenue, Suite 1100, Chicago, IL
60611. E-mail: m-rogers@northwestern.edu
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Received August 15, 2000
Accepted September 28, 2000
Decision Editor: John E. Morley, MB, BCh