Document Detail


Aging effects on postural responses to self-imposed balance perturbations.
MedLine Citation:
PMID:  16214664     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The present study investigated how young and older individuals organize their posture in response to self-induced balance perturbations evoked by oscillatory single limb movements. Eleven old (70.1+/-4.3 years) and nine young (20.1+/-2.4 years) participants performed repeatedly for 5s hip flexion/extension movements using full range of motion and maximum velocity. Two-dimensional joint kinematics (sampling rate: 60Hz), center of pressure (CoP) and EMG activity of tibialis anterior (TA), medial gastrocnemius (MGAS) rectus femoris (RF) and, semitendinosus (ST) in the stance limb were recorded and analysed. Cross-correlation function (CCF) analysis was used to identify the degree of coupling between the swinging limb (SL), center of gravity (CoG) and CoP motions. Old adults significantly limited SL, CoG and CoP range of anterior/posterior (A/P) motion in response to the forceful leg swinging. In the stance limb, significantly lower levels of ankle muscle activity resulted in reduced hip and knee joint excursions and increased ankle instability. By contrast, young performers produced sufficient ankle muscle activity to stabilize the foot to the ground while progressively increasing joint range of motion from the ankle to the hip. Center of pressure and SL movements were strongly correlated in an anti-phase relationship in both age groups. In older adults, however, the relationship between CoG-SL and CoG-CoP movements was neither strong nor synchronous, reflecting a weaker coupling and lack of coordination between component movements. It is concluded that insufficient ankle muscle activity, central integration deficits and increased anxiety to postural threat are important factors implicated for the weaker postural synergies and freezing of degrees of freedom seen in the elderly during performance of single limb oscillations.
Authors:
Vassilia Hatzitaki; Ioannis G Amiridis; Fotini Arabatzi
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Publication Detail:
Type:  Journal Article     Date:  2004-11-23
Journal Detail:
Title:  Gait & posture     Volume:  22     ISSN:  0966-6362     ISO Abbreviation:  Gait Posture     Publication Date:  2005 Nov 
Date Detail:
Created Date:  2005-10-10     Completed Date:  2006-01-31     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  9416830     Medline TA:  Gait Posture     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  250-7     Citation Subset:  IM    
Affiliation:
Motor Control and Learning Laboratory, Department of Physical Education and Sport Sciences, Aristotle University of Thessaloniki, Greece. vaso1@phed.auth.gr
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MeSH Terms
Descriptor/Qualifier:
Adult
Aged
Aging / physiology*
Ankle Joint / physiology
Biomechanics
Electromyography
Hip Joint / physiology
Humans
Knee Joint / physiology
Movement
Muscle, Skeletal / physiology
Postural Balance*
Posture*

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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