Document Detail


Flexion-relaxation response to static lumbar flexion in males and females.
MedLine Citation:
PMID:  12689776     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVE: To determine if creep developed in the lumbar viscoelastic tissues during a period of static flexion elicited changes in the muscular responses of the flexion-relaxation phenomenon. BACKGROUND: Static lumbar flexion is a risk factor in workers, yet the physiological biomechanical and histological processes active in the evolution of the consequent low back disorder were not demonstrated experimentally. Controlled animal studies show that static lumbar flexion develops creep in the associated viscoelastic tissues and elicits spasms and modification of muscle function. Such neuromuscular changes are to be investigated in this study while assessing normal human subjects via the flexion-relaxation phenomenon. METHODS: Male and female subject groups performed three bouts of lumbar flexion-extension before and after a 10 min period of static lumbar flexion. The surface electromyographic from the erector spinae muscles as well as flexion angle were recorded. The angle in which electromyographic diminished during flexion and initiated during extension was determined and subjected to ANOVA with repeated measures to determine any significant changes in the flexion-relaxation response. RESULTS: The erector spinae were active through a significantly larger angle during flexion and initiated activity significantly earlier during extension after static flexion. Females demonstrated more pronounced changes than males. EMG amplitude did not change significantly. Spasms were recorded in more than half of the subjects during the static flexion period. CONCLUSIONS: Creep developed during a short static lumbar flexion elicited significant changes in the muscular activity pattern of the flexion-relaxation phenomenon. The muscles seem to compensate for the loss of tension in the lumbar viscoelastic tissues, while spasms suggest that some micro-damage was incurred to the viscoelastic tissues. RELEVANCE: Static lumbar flexion is shown experimentally as an activity that constitutes an occupational risk factor for the development of low back disorder.
Authors:
Moshe Solomonow; Richard V Baratta; Anthony Banks; Curt Freudenberger; Bing He Zhou
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical biomechanics (Bristol, Avon)     Volume:  18     ISSN:  0268-0033     ISO Abbreviation:  Clin Biomech (Bristol, Avon)     Publication Date:  2003 May 
Date Detail:
Created Date:  2003-04-11     Completed Date:  2003-06-06     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8611877     Medline TA:  Clin Biomech (Bristol, Avon)     Country:  England    
Other Details:
Languages:  eng     Pagination:  273-9     Citation Subset:  IM    
Affiliation:
Occupational Medicine Research Center, Bioengineering Laboratory, Department of Orthopaedic Surgery, Louisiana State University Health Sciences Center, 2025 Gravier Street, Suite 400, New Orleans, LA 70112, USA. msolom@lsuhsc.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Elasticity
Electromyography / methods
Female
Humans
Isometric Contraction / physiology*
Lumbar Vertebrae / physiology*
Male
Movement / physiology*
Muscle Relaxation / physiology
Muscle, Skeletal / physiology*
Posture / physiology
Range of Motion, Articular / physiology*
Rotation
Sex Factors
Viscosity

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


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