Document Detail

Does oxidative capacity affect energy cost? An in vivo MR investigation of skeletal muscle energetics.
MedLine Citation:
PMID:  19255774     Owner:  NLM     Status:  MEDLINE    
Investigations of training effects on exercise energy cost have yielded conflicting results. The purpose of the present study was to compare quadriceps energy cost and oxidative capacity between endurance-trained and sedentary subjects during a heavy dynamic knee extension exercise. We quantified the rates of ATP turnover from oxidative and anaerobic pathways with (31)P-MRS, and we measured simultaneously pulmonary oxygen uptake in order to assess both total ATP production [i.e., energy cost (EC)] and O(2) consumption (O(2) cost) scaled to power output. Seven sedentary (SED) and seven endurance-trained (TRA) subjects performed a dynamic standardized rest-exercise-recovery protocol at an exercise intensity corresponding to 35% of maximal voluntary contraction. We showed that during a dynamic heavy exercise, the O(2) cost and EC were similar in the SED and endurance-trained groups. For a given EC, endurance-trained subjects exhibited a higher relative mitochondrial contribution to ATP production at the muscle level (84 +/- 12% in TRA and 57 +/- 12% in SED; P < 0.01) whereas the anaerobic contribution was reduced (18 +/- 12% in TRA and 44 +/- 11% in SED; P < 0.01). Our results obtained in vivo illustrate that on the one hand the beneficial effects of endurance training are not related to any reduction in EC or O(2) cost and on the other hand that this similar EC was linked to a change regarding the contribution of anaerobic and oxidative processes to energy production, i.e., a greater aerobic energy contribution associated with a concomitant reduction of the anaerobic energy supply.
Gwenael Layec; Aurélien Bringard; Christophe Vilmen; Jean-Paul Micallef; Yann Le Fur; Stéphane Perrey; Patrick J Cozzone; David Bendahan
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-03-03
Journal Detail:
Title:  European journal of applied physiology     Volume:  106     ISSN:  1439-6327     ISO Abbreviation:  Eur. J. Appl. Physiol.     Publication Date:  2009 May 
Date Detail:
Created Date:  2009-05-01     Completed Date:  2009-08-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100954790     Medline TA:  Eur J Appl Physiol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  229-42     Citation Subset:  IM    
Centre de Resonance Magnetique Biologique et Medicale, Faculté de Médecine de Marseille, UMR CNRS 6612, 27 Bd Jean Moulin, 13005, Marseille, France.
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MeSH Terms
Adenosine Triphosphate / metabolism
Anaerobiosis / physiology
Magnetic Resonance Spectroscopy
Muscle, Skeletal / metabolism*
Oxygen Consumption / physiology*
Physical Endurance / physiology
Reg. No./Substance:
56-65-5/Adenosine Triphosphate

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