Muscle glycogen accumulation in trained and untrained individuals

R. C. Hickner, J. S. Fisher, P. A. Hansen, S. B. Racette, C. M. Mìer, M. J. Turner, J. O. Holloszy

Research output: Contribution to journalArticle

Abstract

Muscle glycogen accumulation was compared in six trained cyclists (T) and six untrained subjects (UT) following cycling exercise at 75% VO2peak for 2 hr, terminating with 5 1-min sprints. Subjects ate 10g carbohydrate kg-1 day-1 for 48 hr post-exercise. Muscle glycogen accumulation averaged 71±9 μmol/g (T) and 36±9 μmol/g (UT) during the first 6 hr post-exercise (mean±SEM; p<0.01), and 79±22 μmol/g (T) and 60±9 μmol/g (UT) between 6 and 48 hr post-exercise (n.s.). Muscle glycogen concentration was 164±21 μmol/g (T) and 99±16 μmol/g (UT) 48 hr post-exercise (p<0.05). Glycogen synthase %I was 2.5±0.5, 3.3±0.5, and 1.0±0.3 μmol g-1 · min-1 in T at 0, 6, and 48 hr post-exercise, respectively; corresponding values were 1.2±0.3, 2.7±0.5, and 1.6±0.3μmol g-1 min-1 in UT (p<0.05 at 0 hr). Muscle GLUT-4 content was 3-fold higher in T than UT (p<0.05), and correlated with glycogen accumulation rates (r=0.63, p<0.05). Plasma insulin, plasma C-peptide, and area under the glucose curve were lower in T than UT over the first 6 hr post-exercise (p<0.05). Plasma creatine kinase concentrations (CK) were 125±25 IU/L (T) and 91±9 IU/L (UT) at 0 hr and 112±14 IU/L (T) and 144±22 IU/L (UT) at 48 hr post-exercise (normal: 30-200 IU/L). We conclude that endurance exercise training results in an increased ability to accumulate muscle glycogen after exercise.

Original languageEnglish
Pages (from-to)A214
JournalFASEB Journal
Volume11
Issue number3
StatePublished - Dec 1 1997

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    Hickner, R. C., Fisher, J. S., Hansen, P. A., Racette, S. B., Mìer, C. M., Turner, M. J., & Holloszy, J. O. (1997). Muscle glycogen accumulation in trained and untrained individuals. FASEB Journal, 11(3), A214.