MARSHALL, RYAN N.;
MORGAN, PAUL T.;
SMEUNINX, BENOIT;
QUINLAN, JONATHAN I.;
BROOK, MATTHEW S.;
ATHERTON, PHILIP J.;
SMITH, KENNETH;
WILKINSON, DANIEL J.;
BREEN, LEIGH
Myofibrillar Protein Synthesis and Acute Intracellular Signaling with Elastic Band Resistance Exercise in Young and Older Men
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Medientyp:
E-Artikel
Titel:
Myofibrillar Protein Synthesis and Acute Intracellular Signaling with Elastic Band Resistance Exercise in Young and Older Men
Beteiligte:
MARSHALL, RYAN N.;
MORGAN, PAUL T.;
SMEUNINX, BENOIT;
QUINLAN, JONATHAN I.;
BROOK, MATTHEW S.;
ATHERTON, PHILIP J.;
SMITH, KENNETH;
WILKINSON, DANIEL J.;
BREEN, LEIGH
Beschreibung:
<jats:title>ABSTRACT</jats:title>
<jats:sec>
<jats:title>Purpose</jats:title>
<jats:p>Resistance exercise training (RET) attenuates age-related muscle and strength loss (“sarcopenia”). However, compared with machine-based RET, the efficacy of cost-effective, accessible elastic band RET (EB-RET) for muscle adaptive remodeling lacks supporting mechanistic evidence.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Methods</jats:title>
<jats:p>Eight young (YM; 24 ± 4 yr) and eight older (OM; 68 ± 6 yr) untrained males consumed an oral stable isotope tracer (D<jats:sub>2</jats:sub>O) combined with serial vastus lateralis muscle biopsies to measure integrated myofibrillar protein synthesis (iMyoPS) and regulatory signaling over ~48 h before (habitual) and after an acute bout of EB-RET (6 × 12 repetitions at ~70% of one-repetition maximum). iMyoPS was determined via gas chromatography–pyrolysis–isotope ratio mass spectroscopy and regulatory signaling expression by immunoblot.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Results</jats:title>
<jats:p>Habitual iMyoPS did not differ between YM and OM (1.62% ± 0.21% vs 1.43% ± 0.47%·d<jats:sup>−1</jats:sup>, respectively, <jats:italic toggle="yes">P</jats:italic> = 0.128). There was a significant increase in iMyoPS after EB-RET in YM (2.23% ± 0.69%·d<jats:sup>−1</jats:sup>, <jats:italic toggle="yes">P</jats:italic> = 0.02), but not OM (1.75% ± 0.54%·d<jats:sup>−1</jats:sup>, <jats:italic toggle="yes">P</jats:italic> = 0.30). EB-RET increased the phosphorylation of key anabolic signaling proteins similarly in YM and OM at 1 h postexercise, including p-IRS-1<jats:sup>Ser636/639</jats:sup>, p-Akt<jats:sup>Ser473</jats:sup>, p-4EBP-1<jats:sup>Thr37/46</jats:sup>, p-P70S6K<jats:sup>Thr389</jats:sup>, and p-RPS6<jats:sup>Ser240/244</jats:sup>, whereas p-TSC2<jats:sup>Thr1462</jats:sup> and p-mTOR<jats:sup>Ser2448</jats:sup> increased only in YM (all <jats:italic toggle="yes">P</jats:italic> < 0.05). There were no differences in the expression of amino acid transporters/sensors or proteolytic markers after EB-RET.</jats:p>
</jats:sec>
<jats:sec>
<jats:title>Conclusions</jats:title>
<jats:p>iMyoPS was elevated after EB-RET in YM but not OM. However, the increase in acute anabolic signaling with EB-RET was largely similar between groups. In conclusion, the capacity for EB-RET to stimulate iMyoPS may be impaired in older age. Further work may be necessary to optimize prescriptive programming in YM and OM.</jats:p>
</jats:sec>