Document Detail

The balance recovery mechanisms against unexpected forward perturbation.
MedLine Citation:
PMID:  19472056     Owner:  NLM     Status:  MEDLINE    
Falls are one of the main concerns of the elderly. Proper postural adjustments to maintain balance involve the activation of appropriate muscles to produce force and to relocate the center of body mass (CoM). In this study, biomechanical aspects of dynamic postural responses against forward perturbations were experimentally determined by simultaneous measurements of joint angles and EMG activations. Thirteen young and healthy volunteers took turns standing on a flat platform, and were directed to move in the forward direction by an AC servo-motor set at two different speeds (0.1 and 0.2 m/s). Joint motions were recorded, and they followed the sequence of ankle dorsiflexion, knee flexion, and then hip flexion during the later acceleration phase (AP) in order to maintain postural balance against forward perturbation. Tibialis anterior for the ankle dorsiflexion and biceps femoris for the knee flexion were activated during the second half of the AP as the primary muscles to recover balance. In addition, gastrocnemius, which was related to ankle plantarflexion, and rectus femoris, which was related to knee extension, were activated to maintain balance. Movements of the center of plantar pressure and ground reaction forces in fast-speed perturbation were significantly larger than those in slow-speed perturbation. As a result, the ankle strategy was used for slow-speed perturbation, but the mixed strategy consisting of both ankles and hip were used for fast-speed perturbation.
Sungjae Hwang; Kisik Tae; Ryanghee Sohn; Jungyoon Kim; Jongsang Son; Youngho Kim
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-05-27
Journal Detail:
Title:  Annals of biomedical engineering     Volume:  37     ISSN:  1573-9686     ISO Abbreviation:  Ann Biomed Eng     Publication Date:  2009 Aug 
Date Detail:
Created Date:  2009-07-13     Completed Date:  2009-09-29     Revised Date:  2013-05-30    
Medline Journal Info:
Nlm Unique ID:  0361512     Medline TA:  Ann Biomed Eng     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1629-37     Citation Subset:  IM    
Department of Biomedical Engineering, Institute of Medical Engineering, College of Health Science, Yonsei University, 234 Maeji, Heungup, Wonju, Gangwon 220-710, South Korea.
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MeSH Terms
Accidental Falls
Ankle / physiology
Hip / physiology
Joints / physiology*
Movement / physiology*
Muscle, Skeletal / physiology*
Postural Balance / physiology*
Posture / physiology*

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