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Effect Of Muscle Glycogen Status And Nutrition On Cell Signaling Following Resistance Exercise: 2207: Board #84 June 2 2:00 PM - 3:30 PM

Camera, Donny M.; Burd, Nicholas A.; Phillips, Stuart M. FACSM; Hawley, John A.; Coffey, Vernon G.

Medicine & Science in Sports & Exercise: May 2011 - Volume 43 - Issue 5 - p 583
doi: 10.1249/01.MSS.0000401607.17766.46
D-29 Free Communication/Poster - Macronutrient Metabolism I - Protein and Amino Acids: JUNE 2, 2011 1:00 PM - 6:00 PM: ROOM: Hall B

1RMIT University, Melbourne, Australia. 2McMaster University, Hamilton, ON, Canada.

Email: donny.camera@rmit.edu.au

(No relationships reported)

Training with low muscle glycogen concentration augments adaptation to endurance training, but the effect of glycogen status on anabolic signaling and protein synthesis following resistance exercise (REX) is unknown.

PURPOSE: To determine the effect of divergent glycogen content and subsequent post-exercise nutrition on anabolic signaling target p70S6K Thr389 during the early recovery period following REX.

METHODS: Sixteen resistance trained male subjects (∼23 yr) were randomly assigned to nutrient or placebo groups. After 48 h diet/activity control subjects reported to the laboratory the evening before an experimental trial to perform a glycogen depletion protocol where one-leg undertook cycling exercise to fatigue (LOW vs. normal [NORM]) and subjects then consumed a low carbohydrate (CHO) meal. The next day subjects completed 8 sets of 5 unilateral leg press repetitions at 80% one repetition maximum. Immediately and 2 h post-exercise subjects consumed a 500 ml bolus of protein/CHO (20 g whey + 40 g maltodextrin) or placebo drink. Muscle biopsies were obtained from v. lateralis of both legs at rest, 1 h and 4 h after REX.

RESULTS: The depletion protocol generated divergent muscle glycogen that was higher in the NORM than LOW leg in both nutrient and placebo groups at all time points (P <.05). Muscle glycogen in LOW increased between 1 and 4 h post-exercise in the nutrient (∼84 mmol·kg·dw-1, P <.05) but not placebo group. p70S6KThr389 phosphorylation in LOW increased in both nutrient (15-49 fold) and placebo (∼8 fold) groups 1 h and 4 h post-exercise compared to rest (P <.05) but was only different from rest 1 h post-exercise in NORM in the nutrient group (∼36 fold, P <.05). No differences were observed between NORM and LOW legs 1 h or 4 h post-exercise.

CONCLUSIONS: Despite disparity in muscle glycogen there were similar S6KThr389 phosphorylation responses in NORM and LOW 1 h post-exercise. Our results indicate that commencing high-intensity REX with low muscle glycogen concentration does not suppress phosphorylation of a key component in skeletal muscle translation initiation. Moreover, the possibility exists that translational signaling may be extended with post-exercise nutrient ingestion and the subsequent glycogen resynthesis with low glycogen.

This project was funded by the Australian Sports Commission.

© 2011 American College of Sports Medicine