Post-absorptive muscle protein turnover affects resistance training hypertrophy

Paul T. Reidy, Michael S. Borack, Melissa M. Markofski, Jared M. Dickinson, Christopher Fry, Rachel Deer, Elena Volpi, Blake Rasmussen

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Purpose: Acute bouts of resistance exercise and subsequent training alters protein turnover in skeletal muscle. The mechanisms responsible for the changes in basal post-absorptive protein turnover and its impact on muscle hypertrophy following resistance exercise training are unknown. Our goal was to determine whether post-absorptive muscle protein turnover following 12 weeks of resistance exercise training (RET) plays a role in muscle hypertrophy. In addition, we were interested in determining potential molecular mechanisms responsible for altering post-training muscle protein turnover. Methods: Healthy young men (n = 31) participated in supervised whole body progressive RET at 60–80% 1 repetition maximum (1-RM), 3 days/week for 3 months. Pre- and post-training vastus lateralis muscle biopsies and blood samples taken during an infusion of 13C6 and 15N phenylalanine and were used to assess skeletal muscle protein turnover in the post-absorptive state. Lean body mass (LBM), muscle strength (determined by dynamometry), vastus lateralis muscle thickness (MT), myofiber type-specific cross-sectional area (CSA), and mRNA were assessed pre- and post-RET. Results: RET increased strength (12–40%), LBM (~5%), MT (~15%) and myofiber CSA (~20%) (p < 0.05). Muscle protein synthesis (MPS) increased 24% while muscle protein breakdown (MPB) decreased 21%, respectively. These changes in protein turnover resulted in an improved net muscle protein balance in the basal state following RET. Further, the change in basal MPS is positively associated (r = 0.555, p = 0.003) with the change in muscle thickness. Conclusion: Post-absorptive muscle protein turnover is associated with muscle hypertrophy during resistance exercise training.

Original languageEnglish (US)
Pages (from-to)853-866
Number of pages14
JournalEuropean Journal of Applied Physiology
Volume117
Issue number5
DOIs
StatePublished - May 1 2017

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Keywords

  • Growth
  • mTORC1
  • Ribosome biogenesis
  • Skeletal muscle
  • Strength training

ASJC Scopus subject areas

  • Orthopedics and Sports Medicine
  • Public Health, Environmental and Occupational Health
  • Physiology (medical)

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