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Effect of muscle glycogen availability on maximal exercise performance

  • Mark Hargreaves
  • J. Paul Finn
  • R. T. Withers
  • Garry C. Scroop
  • Malcolm Mackay
  • Rodney J. Snow
  • Michael F. Carey
  • J. Halbert
ORIGINAL ARTICLE

Abstract

This investigation determined the influence of pre-exercise muscle glycogen availability on performance during high intensity exercise. Nine trained male cyclists were studied during 75 s of all-out exercise on an air-braked cycle ergometer following muscle glycogen-lowering exercise and consumption of diets (energy content approximately 14 MJ) that were either high (HCHO – 80% CHO) or low (LCHO – 25% CHO) in carbohydrate content. The exercise-diet regimen was successful in producing differences in pre-exercise muscle glycogen contents [HCHO: 578(SEM 55) mmol · kg−1 dry mass; LCHO: 364 (SEM 58) P < 0.05 mmol · kg−1 dry mass]. Despite this difference in muscle glycogen availability, there were no between trial differences for peak power [HCHO 1185 (SEM 50)W, LCHO 1179 (SEM 48)W], mean power [HCHO 547 (SEM 5)W, LCHO 554 (SEM  8)W] and maximal accumulated oxygen deficit [HCHO 54.4 (SEM 2.3) ml · kg−1, LCHO 54.6 (SEM 2.0) ml · kg−1]. Postexercise muscle lactate contents (HCHO 95.9 (SEM 4.6) mmol · kg−1 dry mass, LCHO 82.7 (SEM 12.3) mmol · kg−1 dry mass, n = 8] were no different between the two trials, nor were venous blood lactate concentrations immediately after and during recovery from exercise. These results would indicate that increased muscle glycogen availability has no direct effect on performance during all-out high intensity exercise.

Key words High intensity exercise   Muscle metabolism Oxygen deficit 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Mark Hargreaves
    • 1
  • J. Paul Finn
    • 2
  • R. T. Withers
    • 2
  • Garry C. Scroop
    • 3
  • Malcolm Mackay
    • 2
  • Rodney J. Snow
    • 4
  • Michael F. Carey
    • 4
  • J. Halbert
    • 2
  1. 1.Department of Physiology, The University of Melbourne, Parkville, 3052, AustraliaAU
  2. 2.Exercise Physiology Laboratory, School of Education, The Flinders University of South Australia, Bedford Park, 5042, AustraliaAU
  3. 3.Department of Physiology, The University of Adelaide, Adelaide, 5001, AustraliaAU
  4. 4.Exercise Metabolism Unit, CRESS, Victoria University of Technology, Footscray, 3011, AustraliaAU

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