Document Detail


V02 'overshoot' during moderate-intensity exercise in endurance-trained athletes: the influence of exercise modality.
MedLine Citation:
PMID:  17981522     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The purpose of this study was to investigate the influence of exercise modality on the 'overshoot' in V(O2) that has been reported following the onset of moderate-intensity (below the gas exchange threshold, GET) exercise in endurance athletes. Seven trained endurance cyclists and seven trained endurance runners completed six square-wave transitions to a work-rate or running speed requiring 80% of mode-specific GET during both cycle and treadmill running exercise. The kinetics of V(O2) was assessed using non-linear regression and any overshoot in V(O2) was quantified as the integrated volume (IV) of O(2) consumed above the steady-state requirement. During cycling, an overshoot in V(O2) was evident in all seven cyclists (IV = 136 +/- 41 ml) and in four runners (IV = 81 +/- 94 ml). During running, an overshoot in V(O2) was evident in four runners (IV = 72 +/- 61 ml) but no cyclists. These data challenge the notion that V(O2) always rises towards a steady-state with near-exponential kinetics in this exercise intensity domain. The greater incidence of the V(O2) overshoot during cycling (11/14 subjects) compared to running (4/14 subjects) indicates that the overshoot phenomenon is related to an interaction between high levels of aerobic fitness and exercise modality. We speculate that a transient loss in muscle efficiency as a consequence of a non-constant ATP requirement following the onset of constant-work-rate exercise or an initially excessive recruitment of motor units (relative to the work-rate) might contribute to the overshoot phenomenon.
Authors:
Andrew E Kilding; Andrew M Jones
Publication Detail:
Type:  Comparative Study; Journal Article     Date:  2007-09-18
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  160     ISSN:  1569-9048     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2008 Feb 
Date Detail:
Created Date:  2008-02-04     Completed Date:  2008-05-06     Revised Date:  2008-06-18    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  139-46     Citation Subset:  IM    
Affiliation:
Institute of Sport and Recreation Research New Zealand, School of Sport and Recreation, Faculty of Health and Environmental Sciences, Auckland University of Technology, Private Bag 92006, Auckland 1020, New Zealand. andrew.kilding@aut.ac.nz
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Physiological
Adult
Bicycling / physiology*
Exercise / physiology*
Exercise Test
Humans
Male
Oxygen / blood
Oxygen Consumption / physiology*
Physical Endurance / physiology*
Physical Fitness / physiology
Reference Values
Running / physiology*
Statistics, Nonparametric
Chemical
Reg. No./Substance:
7782-44-7/Oxygen

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


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