Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men

Nicholas A. Burd, Daniel W.D. West, Daniel R. Moore, Philip J. Atherton, Aaron W. Staples, Todd Prior, Jason E. Tang, Michael J. Rennie, Steven K. Baker, Stuart M. Phillips

Research output: Contribution to journalArticlepeer-review

Abstract

We aimed to determine whether an exercise-mediated enhancement of muscle protein synthesis to feeding persisted 24 h after resistance exercise. We also determined the impact of different exercise intensities (90% or 30% maximal strength) or contraction volume (work-matched or to failure) on the response at 24 h of recovery. Fifteen men (21 ± 1 y, BMI = 24.1 ± 0.8 kg · m22) received a primed, constant infusion of L-[ring-13C6]phenylalanine to measure muscle protein synthesis after protein feeding at rest (FED; 15 g whey protein) and 24 h after resistance exercise (EX-FED). Participants performed unilateral leg exercises: 1) 4 sets at 90% of maximal strength to failure (90FAIL); 2) 30% work-matched to 90FAIL (30WM); or 3) 30% to failure (30FAIL). Regardless of condition, rates of mixed muscle protein and sarcoplasmic protein synthesis were similarly stimulated at FED and EX-FED. In contrast, protein ingestion stimulated rates of myofibrillar protein synthesis above fasting rates by 0.016 ± 0.002%/h and the response was enhanced 24 h after resistance exercise, but only in the 90FAIL and 30FAIL conditions, by 0.038 ± 0.012 and 0.041 ± 0.010, respectively. Phosphorylation of protein kinase B on Ser473 was greater than FED at EX-FED only in 90FAIL, whereas phosphorylation of mammalian target of rapamycin on Ser2448 was significantly increased at EX-FED above FED only in the 30FAIL condition. Our results suggest that resistance exercise performed until failure confers a sensitizing effect on human skeletal muscle for at least 24 h that is specific to the myofibrillar protein fraction.

Original languageEnglish (US)
Pages (from-to)568-573
Number of pages6
JournalJournal of Nutrition
Volume141
Issue number4
DOIs
StatePublished - Apr 1 2011

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

Fingerprint

Dive into the research topics of 'Enhanced amino acid sensitivity of myofibrillar protein synthesis persists for up to 24 h after resistance exercise in young men'. Together they form a unique fingerprint.

Cite this