Myosin heavy chain plasticity in aging skeletal muscle with aerobic exercise training

Adam R. Konopka, Todd A. Trappe, Bozena Jemiolo, Scott W. Trappe, Matthew P. Harber

Research output: Contribution to journalArticlepeer-review

Abstract

To assess myosin heavy chain (MHC) plasticity in aging skeletal muscle with aerobic exercise training, MHC composition was measured at the messenger RNA (mRNA) level and protein level in mixed-muscle homogenates and single myofibers. Muscle samples were obtained from eight nonexercising women (70 ± 2 years) before and after 12 weeks of training (20-45 minutes of cycle exercise per session at 60%-80% heart rate reserve, three to four sessions per week). Training elevated MHC I mRNA (p < .10) and protein (p < .05) in mixed-muscle (54% ± 4% to 61% ± 2%) and single myofibers (42% ± 4% to 52% ± 3%). The increase in MHC I protein was positively correlated (p < .05) with improvements in whole muscle power. Training resulted in a general downregulation of MHC IIa and IIx at the mRNA and protein levels. The training-induced increase in MHC I protein and mRNA demonstrates the maintenance of skeletal muscle plasticity with aging. Furthermore, these data suggest that a shift toward an oxidative MHC phenotype may be beneficial for metabolic and functional health in older individuals.

Original languageEnglish (US)
Pages (from-to)835-841
Number of pages7
JournalJournals of Gerontology - Series A Biological Sciences and Medical Sciences
Volume66 A
Issue number8
DOIs
StatePublished - Aug 2011
Externally publishedYes

Keywords

  • Elderly
  • Endurance training
  • Myofiber
  • Physical activity
  • Sarcopenia

ASJC Scopus subject areas

  • Aging
  • Geriatrics and Gerontology

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