Sex differences in glycolysis during brief, intense isometric contractions

David W. Russ, Ian R. Lanza, Douglas Rothman, Jane A. Kent-Braun

Research output: Contribution to journalArticle

58 Scopus citations

Abstract

We have previously observed less muscle fatigue in women than men under conditions of intact circulation, but similar fatigue across the sexes during local ischemia. Thus, we hypothesized that women utilize their aerobic metabolic pathways to a greater extent than do men. To test this hypothesis, we examined the extent to which different pathways of intramuscular adenosine triphosphate (ATP) production were utilized by men and women during maximal voluntary isometric contractions. Force production during 15-s and 60-s contractions were recorded in parallel sessions. In one session, central activation was assessed with electrical stimulation. In the other, phosphorus magnetic resonance spectroscopy was used to quantify muscle oxidative capacity, and the contributions of glycolysis and oxidative phosphorylation to ATP synthesis during the 60-s contraction. Fatigue and central activation were similar in men and women during both the 15-s and 60-s contractions. The rate constants of phosphocreatine recovery following the 15-s contraction were similar in men and women, indicating similar oxidative capacities. Men exhibited greater acidosis and peak glycolytic rates compared with women during the 60-s contraction, with no differences observed in creatine kinase flux or the percent of oxidative capacity utilized. We conclude that men exhibit greater in vivo glycolysis during brief, intense isometric contractions. Although this metabolic difference did not contribute to any observable differences in fatigue in the present study, these results highlight a potentially important mechanism to explain sex-related differences in muscle function.

Original languageEnglish (US)
Pages (from-to)647-655
Number of pages9
JournalMuscle and Nerve
Volume32
Issue number5
DOIs
StatePublished - Nov 2005

Keywords

  • Acidosis
  • Creatine kinase
  • Fatigue
  • Magnetic resonance spectroscopy
  • Metabolism
  • Oxidative capacity

ASJC Scopus subject areas

  • Physiology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)

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