Postural orientation: Age-related changesin variability and
time-to-boundary
E.E.H. van Wegen a,c,*, R.E.A. van Emmerik a, G.E. Riccio b
a Department of Exercise Science, University of Massachusetts,
110 Totman Building, P.O. Box 37805,
Amherst, MA 01003-7805, USAb Exponent, Inc., Natick, MA, USA
c Department of Physical Therapy, Vrye Universiteit Medisch
Centrum (VUMC), Amsterdam,
The Netherlands
Abstract
The relation between age-specific postural instability and the
detection of stability bound-
aries was examined. Balance control was investigated under
different visual conditions (eyes
open/closed) and postural orientations (forward/backward lean)
while standing on a force
platform. Dependent variables included center of pressure
variability and the time-to-contact
of the center of pressure with the stability boundaries around
the feet (i.e., time-to-boundary).
While leaning maximally, older individuals (ages 5569) showed
increased center of pressure
variability compared to no lean, while younger subjects (ages
2438) showed a decrease. These
significant differences were found only in anteriorposterior
direction. No significant age-spe-
cific differences were found between eyes open and eyes closed
conditions. Time-to-boundary
analysis revealed reduced spatio-temporal stability margins in
older individuals in both ante-
riorposterior and medio-lateral directions. Time-to-boundary
variability, however, was not
significantly different between the groups in both medio-lateral
and anteriorposterior direc-
tion. These results show the importance of boundary relevant
center of pressure measures
in the study of postural control, especially concerning the
lateral instability often observed
in older adults. 2002 Elsevier Science B.V. All rights
reserved.
PsycINFO classification: 2320; 2330; 2860
Keywords: Aging; Balance; Variability; Time-to-boundary;
Postural stability
Human Movement Science 21 (2002) 6184
www.elsevier.com/locate/humov
*Corresponding author. Tel.: +31-20-4440463.
E-mail address: [email protected] (E.E.H. van Wegen).
0167-9457/02/$ - see front matter 2002 Elsevier Science B.V. All
rights reserved.PII: S0167-9457 (02 )00077-5
