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Muscle glycogen utilisation during Rugby match play: Effects of pre-game carbohydrate
Bradley, Warren J. Morehen, James C. Haigh, Julian Clarke, Jon Donovan, Timothy F. Twist, Craig Cotton, Caroline Shepherd, Sam Cocks, Matthew Sharma, Asheesh
Bradley, Warren J.
Morehen, James C.
Haigh, Julian
Clarke, Jon
Donovan, Timothy F.
Twist, Craig
Cotton, Caroline
Shepherd, Sam
Cocks, Matthew
Sharma, Asheesh
Advisors
Editors
Other Contributors
EPub Date
Publication Date
2016-04-22
Submitted Date
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Other Titles
Abstract
Objectives: Although the physical demands of Rugby League (RL) match-play are well-known, the fuel sources supporting energy-production are poorly understood. We therefore assessed muscle glycogen utilisation and plasma metabolite responses to RL match-play after a relatively high (HCHO) or relatively low CHO (LCHO) diet.
Design: Sixteen (mean ± SD age; 18 ± 1 years, body-mass; 88 ± 12 kg, height 180 ± 8 cm) professional players completed a RL match after 36-h consuming a non-isocaloric high carbohydrate (n = 8; 6 g kg day−1) or low carbohydrate (n = 8; 3 g kg day−1) diet.
Methods: Muscle biopsies and blood samples were obtained pre- and post-match, alongside external and internal loads quantified using Global Positioning System technology and heart rate, respectively. Data were analysed using effects sizes ±90% CI and magnitude-based inferences.
Results: Differences in pre-match muscle glycogen between high and low carbohydrate conditions (449 ± 51 and 444 ± 81 mmol kg−1 d.w.) were unclear. High (243 ± 43 mmol kg−1 d.w.) and low carbohydrate groups (298 ± 130 mmol kg−1 d.w.) were most and very likely reduced post-match, respectively. For both groups, differences in pre-match NEFA and glycerol were unclear, with a most likely increase in NEFA and glycerol post-match. NEFA was likely lower in the high compared with low carbohydrate group post-match (0.95 ± 0.39 mmol l−1 and 1.45 ± 0.51 mmol l−1, respectively), whereas differences between the 2 groups for glycerol were unclear (98.1 ± 33.6 mmol l−1 and 123.1 ± 39.6 mmol l−1) in the high and low carbohydrate groups, respectively.
Conclusions: Professional RL players can utilise ∼40% of their muscle glycogen during a competitive match regardless of their carbohydrate consumption in the preceding 36-h.
Citation
Bradley, W., et al. (2016). Muscle glycogen utilisation during Rugby match play: Effects of pre-game carbohydrate. Journal of Science and Medicine in Sport, 19(12), 1033-1038. https://doi.org/10.1016/j.jsams.2016.03.008
Publisher
Elsevier
Journal
Journal of Science and Medicine in Sport
Research Unit
DOI
10.1016/j.jsams.2016.03.008
PubMed ID
PubMed Central ID
Type
Article
Language
en
Description
Series/Report no.
ISSN
1440-2440