| 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
:
|
21865339 - Contribution of motion parallax to segmentation and depth perception. 21849629 - Stereo improves 3d shape discrimination even when rich monocular shape cues are available. 11473579 - Arabidopsis transcriptional regulation by light stress via hydrogen peroxide-dependent ... 23670919 - Highly efficient organic light-emitting diode based on a hidden thermally activated del... 21862639 - Exploring the roles of saturating and supersaturating contrast-response functions in co... 21798789 - Are the force characteristics of synchronous handcycling affected by speed and the meth... |
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: 2013-04-08 |
Medline Journal Info:
|
Nlm Unique ID: 8502536 Medline TA: J Appl Physiol 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...