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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Physiol. | doi: 10.3389/fphys.2019.01084

Comparable Rates of Integrated Myofibrillar Protein Synthesis Between Endurance-Trained Master Athletes and Untrained Older Individuals

  • 1University of Birmingham, United Kingdom
  • 2School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, United Kingdom
  • 3McMaster University, Canada
  • 4Department of Kinesiology, College of Education, University of Georgia, United States

Background: An impaired muscle anabolic response to exercise and protein nutrition is thought to underpin age-related muscle loss, which may be exacerbated by aspects of biological ageing that may not be present in older individuals who have undertaken long-term high-level exercise training, or master athletes (MA). The aim of this study was to compare rested-state and exercise-induced rates of integrated myofibrillar protein synthesis (iMyoPS) and intracellular signaling in endurance trained MA and healthy age-matched untrained individuals (OC).
Methods: In a parallel study design, iMyoPS rates were determined over 48 h in the rested-state and following a bout of unaccustomed resistance exercise (RE) in OC (n=8 males; 73.5 ± 3.3y) and endurance-trained MA (n=7 males; 68.9 ± 5.7y). Intramuscular anabolic signalling was also determined. During the iMyoPS measurement period, physical activity was monitored via accelerometry and dietary intake was controlled.
Results: Anthropometrics, habitual activity and dietary intake were similar between groups. There was no difference in rested-state rates of iMyoPS between OC (1.47 ± 0.06%·day-1) and MA (1.46 ± 0.08%·day-1). RE significantly increased iMyoPS above rest in both OC (1.60 ± 0.08%·day-1, P<0.01) and MA (1.61 ± 0.08%·day-1, P<0.01), with no difference between groups. AktThr308 phosphorylation increased at 1h post-RE in OC (P<0.05), but not MA. No other between-group differences in intramuscular signalling were apparent at any time-point.
Conclusions: While our sample size is limited, these data suggest that rested-state and RE-induced iMyoPS are indistinguishable between MA and OC. Importantly, the OC retain a capacity for RE-induced stimulation of skeletal muscle remodelling.

Keywords: Muscle, Anabolism, Master athlete, Resistance exercise, Sarcopenia

Received: 13 May 2019; Accepted: 07 Aug 2019.

Copyright: © 2019 McKendry, Shad, Smeuninx, Oikawa, Wallis, Greig, Phillips and Breen. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Leigh Breen, University of Birmingham, Birmingham, B15 2TT, United Kingdom, L.breen@bham.ac.uk