Metabolic demands and replenishment of muscle glycogen after a rugby league match simulation protocol

Bradley, Warren J, Hannon, Marcus P, Benford, Victoria, Morehen, James C, Twist, Craig, Shepherd, Sam, Cocks, Matthew, Impey, Samuel G, Cooper, Robert G ORCID: 0000-0001-8337-9973, Morton, James P
et al (show 1 more authors) (2017) Metabolic demands and replenishment of muscle glycogen after a rugby league match simulation protocol. JOURNAL OF SCIENCE AND MEDICINE IN SPORT, 20 (9). pp. 878-883.

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<h4>Objectives</h4>The metabolic requirements of a rugby league match simulation protocol and the timing of carbohydrate provision on glycogen re-synthesis in damaged muscle were examined.<h4>Design</h4>Fifteen (mean±SD: age 20.9±2.9 year, body-mass 87.3±14.1kg, height 177.4±6.0cm) rugby league (RL) players consumed a 6gkgday-1 CHO diet for 7-days, completed a time to exhaustion test (TTE) and a glycogen depletion protocol on day-3, a RL simulated-match protocol (RLMSP) on day-5 and a TTE on day-7. Players were prescribed an immediate or delayed (2-h-post) re-feed post-simulation.<h4>Methods</h4>Muscle biopsies and blood samples were obtained post-depletion, before and after simulated match-play, and 48-h after match-play with PlayerLoad and heart-rate collected throughout the simulation. Data were analysed using effects sizes±90% CI and magnitude-based inferences.<h4>Results</h4>PlayerLoad (8.0±0.7 AUmin-1) and %HRpeak (83±4.9%) during the simulation were similar to values reported for RL match-play. Muscle glycogen very likely increased from immediately after to 48-h post-simulation (272±97 cf. 416±162mmolkg-1d.w.; ES±90%CI) after immediate re-feed, but changes were unclear (283±68 cf. 361±144mmolkg-1d.w.; ES±90%CI) after delayed re-feed. CK almost certainly increased by 77.9±25.4% (0.75±0.19) post-simulation for all players.<h4>Conclusions</h4>The RLMSP presents a replication of the internal loads associated with professional RL match-play, although difficulties in replicating the collision reduced the metabolic demands and glycogen utilisation. Further, it is possible to replete muscle glycogen in damaged muscle employing an immediate re-feed strategy.

Item Type: Article
Uncontrolled Keywords: Physiology, Nutrition, Team-sport, Contact, Metabolism, Carbohydrate
Depositing User: Symplectic Admin
Date Deposited: 31 Aug 2018 14:46
Last Modified: 19 Jan 2023 06:36
DOI: 10.1016/j.jsams.2017.02.005
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