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Cited by 57Cardiovascular and exercise physiologyMuscle metabolism and nutritionMetabolism, Diabetes, and Cancer

Effects of 7 wk of endurance training on human skeletal muscle metabolism during submaximal exercise

LeBlanc, Paul J., Howarth, Krista R., Gibala, Martin J., Heigenhauser, George J. F.·2004·Journal of Applied Physiology
DOI 10.1152/japplphysiol.00517.2004
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Abstract

This is the first study to examine the effects of endurance training on the activation state of glycogen phosphorylase (Phos) and pyruvate dehydrogenase (PDH) in human skeletal muscle during exercise. We hypothesized that 7 wk of endurance training (Tr) would result in a posttransformationally regulated decrease in flux through Phos and an attenuated activation of PDH during exercise due to alterations in key allosteric modulators of these important enzymes. Eight healthy men (22 +/- 1 yr) cycled to exhaustion at the same absolute workload (206 +/- 5 W; approximately 80% of initial maximal oxygen uptake) before and after Tr. Muscle biopsies (vastus lateralis) were obtained at rest and after 5 and 15 min of exercise. Fifteen minutes of exercise post-Tr resulted in an attenuated activation of PDH (pre-Tr: 3.75 +/- 0.48 vs. post-Tr: 2.65 +/- 0.38 mmol.min(-1).kg wet wt(-1)), possibly due in part to lower pyruvate content (pre-Tr: 0.94 +/- 0.14 vs. post-Tr: 0.46 +/- 0.03 mmol/kg dry wt). The decreased pyruvate availability during exercise post-Tr may be due to a decreased muscle glycogenolytic rate (pre-Tr: 13.22 +/- 1.01 vs. post-Tr: 7.36 +/- 1.26 mmol.min(-1).kg dry wt(-1)). Decreased glycogenolysis was likely mediated, in part, by posttransformational regulation of Phos, as evidenced by smaller net increases in calculated muscle free ADP (pre-Tr: 111 +/- 16 vs. post-Tr: 84 +/- 10 micromol/kg dry wt) and P(i) (pre-Tr: 57.1 +/- 7.9 vs. post-Tr: 28.6 +/- 5.6 mmol/kg dry wt). We have demonstrated for the first time that several signals act to coordinately regulate Phos and PDH, and thus carbohydrate metabolism, in human skeletal muscle after 7 wk of endurance training.

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Crossref · 10.1152/japplphysiol.00517.2004

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  • Endurance training influences substrate selection during exercise and thus contributes to the rate of endogenous carbohydrate metabolism during exercise.

    “Endurance training influences substrate selection during exercise and thus contributes to the rate of endogenous carbohydrate metabolism during exercise [21,91,92,93].”

    From Regulation of Energy Substrate Metabolism in Endurance Exercise (2021) · cites this paper as [91]

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Authors
LeBlanc, P. J., Howarth, K. R., Gibala, M. J., & Heigenhauser, G. J. F.
Affiliations
McMaster University (CA)
ORCID
Venue
Journal of Applied Physiology
Publisher
American Physiological Society
Published
2004-12
Volume
97
Issue
6
Pages
2148-2153
ISSN
  • 0161-7567 (ISSN-L)
  • 8750-7587
  • 1522-1601
DOI
10.1152/japplphysiol.00517.2004
OpenAlex
W2134276001
Cited by
56
References
38
Citations by year
2026: 3 · 2025: 2 · 2024: 4 · 2023: 2 · 2022: 1 · 2021: 3 · 2020: 2 · 2019: 1 · 2018: 2 · 2017: 1 · 2016: 1 · 2015: 1 · 2014: 2 · 2013: 3 · 2012: 2
FWCI
4.16
Type
journal article
Language
en
Open access
closed
Locations
  • Journal of Applied Physiology (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Canadian Institutes of Health Research
  • Natural Sciences and Engineering Research Council of Canada
Topics
  • Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Muscle metabolism and nutrition
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Metabolism, Diabetes, and Cancer
Keywords
endurance training, skeletal muscle metabolism, glycogen phosphorylase, pyruvate dehydrogenase, enzyme activation, submaximal exercise, pyruvate, glycogenolysis, carbohydrate metabolism, allosteric regulation, ADP, inorganic phosphate, vastus lateralis, cycling to exhaustion
MeSH terms
Acetylcarnitine, Adenosine Triphosphate, Adult, Blood Glucose, Energy Metabolism, Glycogen, Humans, Male, Oxidation-Reduction, Phosphocreatine, Physical Endurance, Pyruvate Dehydrogenase Complex, Exercise, Muscle, Skeletal, Pyruvic Acid, Lactic Acid, Glycogen Phosphorylase

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