Document Detail


Effects of whole body vibration on motor unit recruitment and threshold.
MedLine Citation:
PMID:  22096119     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Whole body vibration (WBV) has been suggested to elicit reflex muscle contractions but this has never been verified. We recorded from 32 single motor units (MU) in the vastus lateralis of 7 healthy subjects (34 ± 15.4 yr) during five 1-min bouts of WBV (30 Hz, 3 mm peak to peak), and the vibration waveform was also recorded. Recruitment thresholds were recorded from 38 MUs before and after WBV. The phase angle distribution of all MUs during WBV was nonuniform (P < 0.001) and displayed a prominent peak phase angle of firing. There was a strong linear relationship (r = -0.68, P < 0.001) between the change in recruitment threshold after WBV and average recruitment threshold; the lowest threshold MUs increased recruitment threshold (P = 0.008) while reductions were observed in the higher threshold units (P = 0.031). We investigated one possible cause of changed thresholds. Presynaptic inhibition in the soleus was measured in 8 healthy subjects (29 ± 4.6 yr). A total of 30 H-reflexes (stimulation intensity 30% Mmax) were recorded before and after WBV: 15 conditioned by prior stimulation (60 ms) of the antagonist and 15 unconditioned. There were no significant changes in the relationship between the conditioned and unconditioned responses. The consistent phase angle at which each MU fired during WBV indicates the presence of reflex muscle activity similar to the tonic vibration reflex. The varying response in high- and low-threshold MUs may be due to the different contributions of the mono- and polysynaptic pathways but not presynaptic inhibition.
Authors:
Ross D Pollock; Roger C Woledge; Finbarr C Martin; Di J Newham
Related Documents :
21730639 - Localized surface plasmon-induced emission enhancement of a green light-emitting diode.
22191509 - Isometric knee extension force measured using a handheld dynamometer with and without b...
21678119 - Striking presence of egyptian blue identified in a painting by giovanni battista benven...
22225379 - Sensory coding in oscillatory electroreceptors of paddlefish.
6058009 - A mutagenic effect of visible light mediated by endogenous pigments in euglena gracilis.
21512959 - Automatic priming of grip force following action observation.
921609 - Remote masking generated by high-frequency two-tone complexes.
21190869 - The tickly homunculus and the origins of spontaneous sensations arising on the hands.
21110599 - Dissociation of perceptual judgments of "what" and "where" in an ambiguous auditory scene.
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-11-17
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  112     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-02-03     Completed Date:  2012-08-23     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  United States    
Other Details:
Languages:  eng     Pagination:  388-95     Citation Subset:  IM    
Affiliation:
Centre of Human and Aerospace Physiological Sciences, King's College London, UK. ross.pollock@kcl.ac.uk
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Action Potentials / physiology*
Adult
Electromyography / methods
H-Reflex / physiology
Humans
Motor Cortex / physiology
Muscle Contraction / physiology*
Muscle, Skeletal / physiology*
Recruitment, Neurophysiological / physiology*
Synapses / physiology
Vibration
Comments/Corrections

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


Previous Document:  Middle cerebral artery alterations in a rat chronic hypoperfusion model.
Next Document:  Spaceflight regulates ryanodine receptor subtype 1 in portal vein myocytes in the opposite way of hy...