Myogenic, matrix, and growth factor mRNA expression in human skeletal muscle: effect of contraction intensity and feeding

Muscle Nerve. 2013 May;47(5):748-59. doi: 10.1002/mus.23667. Epub 2013 Mar 21.

Abstract

Introduction: We examined short-term (3-hour) and long-term (12-week) training effects after heavy load [HL; 70% 1RM] and light load (LL; 16% 1RM) exercise.

Methods: mRNA expression of genes involved in skeletal muscle remodeling were analyzed and muscle activity (EMG measurements) was measured.

Results: Relative muscle activity differed between HL and LL resistance exercise, whereas median power frequency was even, suggesting an equal muscle-fiber-type recruitment distribution. mRNA expression of Myf6, myogenin, and p21 was mostly increased, and myostatin was mostly depressed by HL resistance exercise. No major differences were seen in atrophy-related genes between HL and LL resistance exercise. No changes were seen over 12-week training for any of the targets.

Conclusions: Resistance exercise at LL and HL elevated the expression of genes involved in skeletal muscle hypertrophy, although the greatest response was from HL. However, no long-term effect from either LL or HL resistance exercise was seen on basal levels of the mRNA targets.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Electromyography
  • Exercise / physiology*
  • Gene Expression Regulation
  • Humans
  • Male
  • Muscle Contraction / physiology*
  • Muscle, Skeletal / metabolism
  • Muscle, Skeletal / physiology*
  • Myostatin / genetics
  • Myostatin / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Resistance Training*

Substances

  • Myostatin
  • RNA, Messenger