Impact of repeated bouts of eccentric exercise on myogenic gene expression

Eur J Appl Physiol. 2007 Nov;101(4):427-36. doi: 10.1007/s00421-007-0510-z. Epub 2007 Jul 20.


Evidence indicates that repeated-bouts of eccentric exercise (EE) do not exacerbate the extent of muscle damage indices, as compared to a single-bout. We hypothesized that molecular adaptations, under repeated-bouts of EE, would include suppression of muscle repair inhibitory factors such as myostatin and up-regulation of muscle repair positive regulatory factors such as myogenic regulatory factors (MRFs). Fifteen males were recruited for this study. The exercise group (n=9) successfully completed six sets of 15 reps of maximum voluntary eccentric contractions, for six consecutive days, using a dynamometer (Multicont-II). Blood and muscle biopsy samples were obtained from each subject 1 week prior to exercise, 2 days post the first training session, and 24 h after the last training session. Gene expression levels were determined using real-time RT-PCR. Blood samples were analyzed for creatine kinase (CK) and lactate-dehydrogenase (LDH) activity. Repeated-bouts of EE induced a large down-regulation of myostatin mRNA (-73%) which persisted throughout the study. The responses of MRFs were mild. At day 3 only myogenin increased significantly (1.9 fold) while MyoD decreased by 45%. Surprisingly, at day 7, despite the presence of muscle damage indices, all MRFs returned to the pre-exercise levels. The results of the present study showed that repeated-bouts of EE, for six consecutive days, dramatically decreased Myostatin mRNA expression but impaired the expression patterns of MRFs such that, with the exception of myogenin that showed a moderate non-sustained increase, MyoD and MYf5 response was minimal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cell Differentiation / physiology
  • Cell Proliferation
  • Creatine Kinase / metabolism
  • DNA, Complementary / biosynthesis
  • DNA, Complementary / genetics
  • Exercise / physiology*
  • Gene Expression / physiology*
  • Humans
  • Ki-67 Antigen / metabolism
  • L-Lactate Dehydrogenase / metabolism
  • Male
  • Muscle Contraction / physiology
  • Muscle Strength / physiology
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / physiology
  • MyoD Protein / biosynthesis
  • MyoD Protein / genetics
  • Myogenic Regulatory Factor 5 / biosynthesis
  • Myogenic Regulatory Factor 5 / genetics
  • Myogenic Regulatory Factors / biosynthesis*
  • Myogenic Regulatory Factors / genetics*
  • Myostatin
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transforming Growth Factor beta / biosynthesis*
  • Up-Regulation / physiology
  • p21-Activated Kinases / biosynthesis
  • p21-Activated Kinases / genetics


  • DNA, Complementary
  • Ki-67 Antigen
  • MSTN protein, human
  • MYF5 protein, human
  • MyoD Protein
  • Myogenic Regulatory Factor 5
  • Myogenic Regulatory Factors
  • Myostatin
  • RNA, Messenger
  • Transforming Growth Factor beta
  • L-Lactate Dehydrogenase
  • p21-Activated Kinases
  • Creatine Kinase