[Abstract Title]. - Society for Neuroscience

Disclosures: S. Tseng , None; S.J. Stanhope, None; S.M. Morton, None.
Poster
275. Posture: Kinematics and Muscle Activity
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 275.18/JJ33
Topic: D.16.d. Kinematics and Muscle Activity
Title: Effects of age and target height on dynamic balance control during reaching
Authors: *M.-H. HUANG, M. A. MOUSIGIAN, S. H. BROWN;
Div. Kinesiol, Univ. Michigan, Ann Arbor, MI
Abstract: The control of balance during functional tasks such as reaching from standing requires
the production of appropriate anticipatory (APAs) and compensatory postural responses. In older
individuals, deterioration in the magnitude and timing of postural responses frequently occurs,
leading to instability and increased risk of falls. While some studies have indicated that reaching
to high targets produces increased instability (Row and Cavanagh, 2007), to what extent target
location affects dynamic balance control during free standing in the elderly has not been
systematically addressed. This study, therefore, examined the effects of age and reach target
height on the control of center of pressure (COP).
Twelve young (20 ± 1 yr) and 16 older (74 ± 5 yrs) participants reached to targets at various
heights (above head, shoulder, low), with the dominant or non-dominant hand as fast as possible.
Targets were at 110% of arm‟s length away and vertically aligned with the shoulder joint of the
reaching arm. Kinematics of hand movements were measured with a 3-D motion analysis system
(MotionStar). COP data were derived from ground reaction forces recorded by a force plate
(AMTI AccuSway Plus).
The magnitude of COP posterior displacement associated with APAs was significantly greater in
older than young adults (p=0.03) at the lowest compared to the higher targets (p