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Appears in Collections:Faculty of Health Sciences and Sport Journal Articles
Peer Review Status: Refereed
Title: Fuel for the work required: A practical approach to amalgamating train-low paradigms for endurance athletes
Authors: Impey, Samuel G
Hammond, Kelly M
Shepherd, Sam O
Sharples, Adam P
Stewart, Claire
Limb, Marie
Smith, Kenneth
Philp, Andrew
Jeromson, Stewart
Hamilton, David Lee
Close, Graeme L
Morton, James P
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Issue Date: 24-May-2016
Citation: Impey SG, Hammond KM, Shepherd SO, Sharples AP, Stewart C, Limb M, Smith K, Philp A, Jeromson S, Hamilton DL, Close GL & Morton JP (2016) Fuel for the work required: A practical approach to amalgamating train-low paradigms for endurance athletes, Physiological Reports, 4 (10), Art. No.: e12803.
Abstract: Using an amalgamation of previously studied “train‐low” paradigms, we tested the effects of reduced carbohydrate (CHO) but high leucine availability on cell‐signaling responses associated with exercise‐induced regulation of mitochondrial biogenesis and muscle protein synthesis (MPS). In a repeated‐measures crossover design, 11 males completed an exhaustive cycling protocol with high CHO availability before, during, and after exercise (HIGH) or alternatively, low CHO but high protein (leucine enriched) availability (LOW+LEU). Muscle glycogen was different (P<0.05) pre‐exercise (HIGH: 583±158, LOW+LEU: 271±85 mmol kg −1 dw) but decreased (P<0.05) to comparable levels at exhaustion (≈100 mmol kg−1 dw). Despite differences (P<0.05) in exercise capacity (HIGH: 158±29, LOW+LEU: 100±17min), exercise induced (P<0.05) comparable AMPKα2 (3–4‐fold) activity, PGC‐1α(13‐fold), p53 (2‐fold), Tfam (1.5‐fold), SIRT1 (1.5‐fold), Atrogin 1 (2‐fold), and MuRF1 (5‐fold) gene expression at 3h post‐exercise. Exhaustive exercise suppressed p70S6K activity to comparable levels immediately post‐exercise (≈20 fmol min−1 mg−1). Despite elevated leucine availability post‐exercise, p70S6K activity remained suppressed (P<0.05) 3h post‐exercise in LOW+LEU (28±14 fmol min−1 mg−1), whereas muscle glycogen resynthesis (40 mmol kg−1 dwh−1) was associated with elevated (P<0.05) p70S6K activity in HIGH (53±30 fmol min−1 mg−1). We conclude: (1) CHO restriction before and during exercise induces “work‐efficient” mitochondrial‐related cell signaling but; (2) post‐exercise CHO and energy restriction maintains p70S6K activity at basal levels despite feeding leucine‐enriched protein. Our data support the practical concept of “fuelling for the work required” as a potential strategy for which to amalgamate train‐low paradigms into periodized training programs.
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Rights: © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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