Document Detail


Influence of priming exercise on muscle [PCr] and pulmonary O2 uptake dynamics during 'work-to-work' knee-extension exercise.
MedLine Citation:
PMID:  20417317     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Metabolic transitions from rest to high-intensity exercise were divided into two discrete steps (i.e., rest-to-moderate-intensity (R-->M) and moderate-to-high-intensity (M-->H)) to explore the effect of prior high-intensity 'priming' exercise on intramuscular [PCr] and pulmonary VO₂ kinetics for different sections of the motor unit pool. It was hypothesized that [PCr] and VO₂ kinetics would be unaffected by priming during R-->M exercise, but that the time constants (tau) describing the fundamental [PCr] response and the phase II VO₂ response would be significantly reduced by priming for M-->H exercise. On three separate occasions, six male subjects completed two identical R-->M/M-->H 'work-to-work' prone knee-extension exercise bouts separated by 5min rest. Two trials were performed with measurement of pulmonary VO₂ and the integrated electromyogram (iEMG) of the right m. vastus lateralis. The third trial was performed within the bore of a 1.5-T superconducting magnet for (31)P-MRS assessment of muscle metabolic responses. Priming did not significantly affect the [PCr] or VO₂ tau during R-->M ([PCr] tau Unprimed: 24+/-16 vs. Primed: 22+/-14s; VO₂ tau Unprimed: 26+/-8 vs. Primed: 25+/-9s) or M-->H transitions ([PCr] tau Unprimed: 30+/-5 vs. Primed: 32+/-7s; VO₂ tau Unprimed: 37+/-5 vs. Primed: 38+/-9s). However, it did reduce the amplitudes of the [PCr] and VO₂ slow components by 50% and 46%, respectively, during M-->H (P<0.05 for both comparisons). These effects were accompanied by iEMG changes suggesting reduced muscle fiber activation during M-->H exercise after priming. It is concluded that the tau for the initial exponential change of muscle [PCr] and pulmonary VO₂ following the transition from moderate-to-high-intensity prone knee-extension exercise is not altered by priming exercise.
Authors:
Fred J Dimenna; Jonathan Fulford; Stephen J Bailey; Anni Vanhatalo; Daryl P Wilkerson; Andrew M Jones
Related Documents :
10613427 - Creatine supplementation--part ii: in vivo magnetic resonance spectroscopy.
8167137 - Measurement of unidirectional p(i)-->atp flux in lamb myocardium in vivo.
1560737 - Exertional heatstroke and muscle metabolism: an in vivo 31p-mrs study.
8853467 - Endurance-trained and untrained skeletal muscle bioenergetics observed with magnetic re...
21936647 - The effects of acute exercise on temporal generalization.
17335467 - Effect of moderate aerobic exercise on sympatho-vagal balance in type 2 diabetic patients.
Publication Detail:
Type:  Journal Article     Date:  2010-04-22
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  172     ISSN:  1878-1519     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2010 Jun 
Date Detail:
Created Date:  2010-06-14     Completed Date:  2010-09-17     Revised Date:  2010-10-25    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  15-23     Citation Subset:  IM    
Copyright Information:
Copyright 2010 Elsevier B.V. All rights reserved.
Affiliation:
School of Sport and Health Sciences, St. Luke's Campus, University of Exeter, Heavitree Road, Exeter, Devon EX1 2LU, UK.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Adult
Electromyography
Exercise / physiology*
Humans
Knee Joint / physiology*
Magnetic Resonance Spectroscopy / methods
Male
Muscle, Skeletal / metabolism*
Nonlinear Dynamics
Oxygen Consumption / physiology*
Physical Endurance / physiology*
Pulmonary Gas Exchange / physiology
Quadriceps Muscle / metabolism
Young Adult

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


Previous Document:  Breathing and locomotion: comparative anatomy, morphology and function.
Next Document:  Distribution of polyethylene wear particles and bone fragments in periprosthetic tissue around total...