Document Detail

Motor unit synchronization between medial and lateral vasti muscles.
MedLine Citation:
PMID:  15908269     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: Accurate neuromuscular control of the patellofemoral joint is important in knee joint mechanics. Strategies to coordinate the vasti muscles, such as motor unit synchronization, may simplify control of patellar tracking. This study investigated motor unit synchronization between vastus medialis (VM) and lateralis (VL). METHODS: Electromyographic (EMG) recordings of single motor unit action potentials (MUAPs) were made from VM and single- and multi-unit recordings were made from VL. Synchronization was quantified from peaks in the cross-correlogram generated from single MUAP pairs in VL and VM. The proportion of motor units in VM with synchronized firing in VL was also quantified from peaks in averages of multiunit VL EMG triggered from the VM MUAP. RESULTS: A high degree of synchronization of motor unit firing between VM and VL was identified. Results were similar for cross-correlation ( approximately 45% of cases) and triggered averages (approximately 41% of cases). CONCLUSIONS: The data suggest that synchronization between VM and VL is higher than expected. Agreement between traditional cross-correlation and triggered averaging methods suggest that this new technique may provide a more clinically viable method to quantify synchronization. SIGNIFICANCE: High synchronization between VM and VL may provide a solution to simplify control of the mechanically unstable patellofemoral joint.
Rebecca Mellor; Paul Hodges
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology     Volume:  116     ISSN:  1388-2457     ISO Abbreviation:  Clin Neurophysiol     Publication Date:  2005 Jul 
Date Detail:
Created Date:  2005-06-14     Completed Date:  2005-08-11     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  100883319     Medline TA:  Clin Neurophysiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  1585-95     Citation Subset:  IM    
Division of Physiotherapy, School of Health and Rehabilitation Sciences, The University of Queensland, Brisbane, Qld 4072, Australia.
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MeSH Terms
Action Potentials / physiology
Electromyography / methods
Gait / physiology
Isometric Contraction / physiology*
Knee Joint / physiology*
Motor Neurons / physiology*
Muscle, Skeletal / innervation,  physiology*
Neuromuscular Junction / physiology*
Postural Balance / physiology
Posture / physiology
Reaction Time / physiology
Thigh / innervation,  physiology*

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