Effects of different intensities of resistance exercise on regulators of myogenesis

J Strength Cond Res. 2009 Nov;23(8):2179-87. doi: 10.1519/JSC.0b013e3181bab493.


A single bout of high-intensity resistance exercise is capable of activating the expression of various genes in skeletal muscle involved in hypertrophy such as myosin heavy chain (MHC) isoforms, myogenic regulatory factors (MRFs), and growth factors. However, the specific role exercise intensity plays on the expression of these genes is not well defined. The purpose of this study was to investigate the effects of exercise intensity on MHC (type I, IIA, IIX), MRF (Myo-D, myogenin, MRF-4, myf5), and growth factor (insulin-like growth factor [IGF]-1, IGF-1 receptor [IGF-R1], mechano-growth factor [MGF]) mRNA expression. Thirteen male participants (21.5 +/- 2.9 years, 86.1 +/- 19.5 kg, 69.7 +/- 2.7 in.) completed bouts of resistance exercise involving 4 sets of 18-20 repetitions with 60-65% 1 repetition maximum (1RM) and 4 sets of 8-10 repetitions with 80-85% 1RM. Vastus lateralis biopsies were obtained immediately before exercise, and at 30 minutes, 2 hours, and 6 hours after each bout. The levels of mRNA expression were determined using real-time polymerase chain reaction. Data were analyzed using 2 x 4 multivariate analysis of variance (p <or= 0.05). For both intensities, MHC type IIX, IGF-1, IGF-R1, MGF, Myo-D, myogenin, MRF-4, and myf5 mRNA were all significantly increased in response to resistance exercise by 2 hours after exercise, whereas myostatin and the cyclin-dependent kinase inhibitor p27(kip) were decreased at 2 hours after exercise (p < 0.05). Resistance exercise between 60-85% 1RM upregulates the mRNA expression of MHC and factors involved in myogenic activation of satellite cells while concomitantly decreasing expression of myogenic inhibitors.

Publication types

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

MeSH terms

  • Analysis of Variance
  • Biomarkers / metabolism*
  • Biopsy
  • Cross-Over Studies
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Male
  • Muscle Development / genetics
  • Muscle Development / physiology*
  • Muscle, Skeletal / metabolism*
  • Myogenic Regulatory Factors / genetics
  • Myogenic Regulatory Factors / metabolism
  • Myosin Heavy Chains / genetics
  • Myosin Heavy Chains / metabolism
  • Myostatin / genetics
  • Myostatin / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism*
  • Resistance Training / methods*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Time Factors
  • Up-Regulation
  • Young Adult


  • Biomarkers
  • Intercellular Signaling Peptides and Proteins
  • Myogenic Regulatory Factors
  • Myostatin
  • RNA, Messenger
  • Myosin Heavy Chains