Document Detail

Effect of age on anticipatory postural adjustments in unilateral arm movement.
MedLine Citation:
PMID:  16213140     Owner:  NLM     Status:  MEDLINE    
Aging is frequently accompanied by a deterioration in postural control. Accordingly, the elderly adopt postural strategies in order to maintain balance. The purpose of this study was to compare anticipatory postural adjustments in (healthy) 10 young and 10 elderly subjects using electromyography (EMG) and biomechanical parameters. While standing on a force platform, subjects performed voluntary, arm-raising movements under five conditions: self-paced at three different velocities, self-paced with load and an externally triggered, both at maximal velocity. The force platform provided information on vertical torque (T(z)) and center of pressure anteroposterior displacements (COP). EMG activity was recorded from the biceps femoris, quadriceps, tibialis anterior and soleus muscles. Voluntary movements were associated with an early COP backward shift and an anticipatory T(z). At low velocity, elderly subjects did not show any impairment in stability. At maximal velocity, T(z) was delayed in all conditions in the elderly group, whereas COP latency was reduced only in the self-paced condition without load. Despite this decrease in anticipation, the movement was performed at the same velocity as in younger subjects. The elderly adopted various muscle strategies in order to perform the same movement with less stability. In the self-paced condition, elderly subjects used a hip strategy, whereas young subjects used an ankle strategy. In the triggered condition, the strategy corresponded to increased activation of certain thigh muscles, rather than a sequence modification. Hence, local muscle strategies were used to counteract the overall delay in postural preparation revealed by biomechanical parameters.
Séverine Bleuse; François Cassim; Jean-Louis Blatt; Etienne Labyt; Philippe Derambure; Jean-Daniel Guieu; Luc Defebvre
Publication Detail:
Type:  Comparative Study; Journal Article     Date:  2005-10-04
Journal Detail:
Title:  Gait & posture     Volume:  24     ISSN:  0966-6362     ISO Abbreviation:  Gait Posture     Publication Date:  2006 Oct 
Date Detail:
Created Date:  2006-09-11     Completed Date:  2007-01-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9416830     Medline TA:  Gait Posture     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  203-10     Citation Subset:  IM    
Department of Clinical Neurophysiology, Laboratory of Movement Analysis, Salengro Hospital, CHU, Lille University Medical Center, F-59037 Lille Cedex, France.
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MeSH Terms
Age Factors
Arm / physiology*
Movement / physiology*
Muscle, Skeletal / physiology
Proprioception / physiology*
Reaction Time / physiology
Weight-Bearing / physiology

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