Karbohydrater + protein er best etter trening

4E-BP1 og S6K1 er signaler som er meget viktige for muskelvekst. Denne studien viser at karbohydrater alene ikke er tilstrekkelig for å gi optimale nivåer av disse signalene i forbindelse med trening, og at kombinasjonen protein+karbohydrater er nødvendig. Det er jo mange som påstår at man kun skal innta karbohydrater rundt treningsøkta, og vente med å innta protein til 1 time etter trening - men dette strider helt med forskningen som foreligger om viktigheten av korrekt næringsinntak både før, under og etter trening, og dette er nok et studie som avkrefter denne myten.

J Nutr. 2007 Aug;137(8):1880-6.

Protein Ingestion Further Augments S6K1 Phosphorylation in Skeletal Muscle Following Resistance Type Exercise in Males.

Koopman R, Pennings B, Zorenc AH, van Loon LJ.

Departments of Movement Sciences and 3Human Biology, Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Maastricht University, Maastricht 6200 MD, The Netherlands.

Our objective was to determine the impact of carbohydrate and/or protein ingestion before and after exercise on ribosomal protein S6 kinase (S6K1) and S6 phosphorylation status in human skeletal muscle tissue. Seven healthy, untrained men (22.5 +/- 0.9 y) were randomly assigned to 2 cross-over experiments. Before, immediately after, and 1 h after a single bout of resistance exercise, subjects consumed 0.3 g.kg(-1) carbohydrate with or without 0.3 g.kg(-1) protein hydrolysate (CHO+PRO and CHO, respectively). Muscle biopsies were taken before and immediately after exercise and after 1 and 4 h of postexercise recovery to determine 4E-BP1, S6K1 (both T(421)/S(424) and T(389)), and S6 phosphorylation status. Following resistance exercise, 4E-BP1 phosphorylation was reduced to a greater extent in the CHO treatment (-48 +/- 7%) than in the CHO+PRO treatment (-15 +/- 14%, P < 0.01). During recovery, 4E-BP1 phosphorylation increased in both experiments (P < 0.01), and tended to be higher in the CHO+PRO test (P = 0.08). S6K1 phosphorylation at T(421)/S(424) substantially increased following exercise and remained elevated during recovery with no differences between treatments. In contrast to the CHO treatment (-4 +/- 2%), S6K1 phosphorylation at T(389) was higher following exercise in the CHO+PRO treatment only (+78 +/- 2%, P < 0.01). During recovery, S6K1 phosphorylation at T(389) remained higher in CHO+PRO than in CHO (P < 0.05). S6 phosphorylation was substantially higher following exercise in the CHO+PRO (1.69 +/- 0.35) than in the CHO experiment (0.45 +/- 0.07, P < 0.01) and remained elevated during recovery (P < 0.05). We conclude that the availability of dietary protein further enhances phosphorylation of S6K1 during recovery from resistance type exercise.