Acute and long-term effects of resistance exercise with or without protein ingestion on muscle hypertrophy and gene expression

Amino Acids. 2009 Jul;37(2):297-308. doi: 10.1007/s00726-008-0150-6. Epub 2008 Jul 27.


The effects of timed ingestion of high-quality protein before and after resistance exercise are not well known. In this study, young men were randomized to protein (n = 11), placebo (n = 10) and control (n = 10) groups. Muscle cross-sectional area by MRI and muscle forces were analyzed before and after 21 weeks of either heavy resistance training (RT) or control period. Muscle biopsies were taken before, and 1 and 48 h after 5 x 10 repetition leg press exercise (RE) as well as 21 weeks after RT. Protein (15 g of whey both before and after exercise) or non-energetic placebo were provided to subjects in the context of both single RE bout (acute responses) as well as each RE workout twice a week throughout the 21-week-RT. Protein intake increased (P < or = 0.05) RT-induced muscle cross-sectional area enlargement and cell-cycle kinase cdk2 mRNA expression in the vastus lateralis muscle suggesting higher proliferating cell activation response with protein supplementation. Moreover, protein intake seemed to prevent 1 h post-RE decrease in myostatin and myogenin mRNA expression but did not affect activin receptor IIb, p21, FLRG, MAFbx or MyoD expression. In conclusion, protein intake close to resistance exercise workout may alter mRNA expression in a manner advantageous for muscle hypertrophy.

Publication types

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

MeSH terms

  • Activin Receptors, Type II / genetics
  • Activin Receptors, Type II / metabolism
  • Adipose Tissue
  • Adult
  • Body Height
  • Body Weight
  • Dietary Proteins / administration & dosage*
  • Dietary Supplements*
  • Humans
  • Hypertrophy
  • Male
  • Muscle Proteins / genetics
  • Muscle Proteins / metabolism
  • Muscle, Skeletal* / anatomy & histology
  • Muscle, Skeletal* / physiology
  • Myostatin / genetics
  • Myostatin / metabolism
  • Placebos
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Resistance Training*
  • SKP Cullin F-Box Protein Ligases / genetics
  • SKP Cullin F-Box Protein Ligases / metabolism
  • Young Adult


  • Dietary Proteins
  • Muscle Proteins
  • Myostatin
  • Placebos
  • RNA, Messenger
  • FBXO32 protein, human
  • SKP Cullin F-Box Protein Ligases
  • Activin Receptors, Type II
  • activin receptor type II-B