HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 97/6/2148    most recent 00517.2004v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by LeBlanc, P. J. Articles by Heigenhauser, G. J. F. Search for Related Content PubMed PubMed Citation Articles by LeBlanc, P. J. Articles by Heigenhauser, G. J. F.

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

¹Department of Medicine, McMaster University, Hamilton, Ontario L8N 3Z5; and ²Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada L8S 4K1

Submitted 13 May 2004 ; accepted in final form 24 June 2004

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; 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 µmol/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.

energy status; pyruvate; pyruvate dehydrogenase

This article has been cited by other articles:

				B. R. McKay, D. H. Paterson, and J. M. Kowalchuk Effect of short-term high-intensity interval training vs. continuous training on O2 uptake kinetics, muscle deoxygenation, and exercise performance J Appl Physiol, July 1, 2009; 107(1): 128 - 138. [Abstract] [Full Text] [PDF]

				Y. Li, R. K. Dash, J. Kim, G. M. Saidel, and M. E. Cabrera Role of NADH/NAD+ transport activity and glycogen store on skeletal muscle energy metabolism during exercise: in silico studies Am J Physiol Cell Physiol, January 1, 2009; 296(1): C25 - C46. [Abstract] [Full Text] [PDF]

				P. J. LeBlanc, M. Mulligan, A. Antolic, L. MacPherson, J. G. Inglis, D. Martin, B. D. Roy, and S. J. Peters Skeletal muscle type comparison of pyruvate dehydrogenase phosphatase activity and isoform expression: effects of obesity and endurance training Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2008; 295(4): R1224 - R1230. [Abstract] [Full Text] [PDF]

				M. Mourtzakis, T. E. Graham, J. Gonzalez-Alonso, and B. Saltin Glutamate availability is important in intramuscular amino acid metabolism and TCA cycle intermediates but does not affect peak oxidative metabolism J Appl Physiol, August 1, 2008; 105(2): 547 - 554. [Abstract] [Full Text] [PDF]

				K. A. Burgomaster, G. J. F. Heigenhauser, and M. J. Gibala Effect of short-term sprint interval training on human skeletal muscle carbohydrate metabolism during exercise and time-trial performance J Appl Physiol, June 1, 2006; 100(6): 2041 - 2047. [Abstract] [Full Text] [PDF]