Document Detail


The initiation of the swing phase in human infant stepping: importance of hip position and leg loading.
MedLine Citation:
PMID:  11034628     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Hip extension and low load in the extensor muscles are important sensory signals that allow a decerebrate or spinal cat to advance from the stance phase to the swing phase during walking. We tested whether the same sensory information controlled the phases of stepping in human infants. Twenty-two infants between the ages of 5 and 12 months were studied during supported stepping on a treadmill. Forces exerted by the lower limbs, surface electromyography (EMG) from muscles, and the right hip angle were recorded. The whole experimental session was videotaped. The hip position and the amount of load experienced by the right limb were manipulated during stepping by changing the position of the foot during the stance phase or by applying manual pressure on the pelvic crest. Disturbances with different combinations of hip position and load were used. The stance phase was prolonged and the swing phase delayed when the hip was flexed and the load on the limb was high. In contrast, stance phase was shortened and swing advanced when the hip was extended and the load was low. The results were remarkably similar to those in reduced preparations of the cat. They thus suggest that the behaviour of the brainstem and spinal circuitry for walking may be similar between human infants and cats. There was an inverse relationship between hip position and load at the time of swing initiation, indicating the two factors combine to regulate the transition.
Authors:
M Y Pang; J F Yang
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of physiology     Volume:  528 Pt 2     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2000 Oct 
Date Detail:
Created Date:  2000-12-19     Completed Date:  2000-12-19     Revised Date:  2013-06-11    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  389-404     Citation Subset:  IM    
Affiliation:
Department of Physical Therapy and Division of Neuroscience, University of Alberta, Edmonton, Alberta, Canada T6G 2G4.
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MeSH Terms
Descriptor/Qualifier:
Animals
Biomechanics
Brain Stem / physiology
Cats
Decerebrate State / physiopathology
Electromyography
Hip / physiology
Humans
Infant
Leg / physiology
Posture / physiology
Species Specificity
Spinal Cord / physiology
Walking / physiology*
Comments/Corrections

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


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