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J Sci Med Sport. 2016 Dec;19(12):1033-1038. doi: 10.1016/j.jsams.2016.03.008. Epub 2016 Apr 22.

Muscle glycogen utilisation during Rugby match play: Effects of pre-game carbohydrate.

Author information

1
Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, UK.
2
Widnes Vikings Rugby, UK.
3
Sport and Exercise Sciences, Glyndwr University, UK.
4
Department of Sport and Exercise Sciences, University of Chester, UK.
5
Department of Rheumatology, Aintree University Hospital, UK.
6
Department of Renal Medicine, Royal Liverpool Hospital, UK.
7
MRC Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing, University of Liverpool, UK.
8
Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, UK. Electronic address: g.l.close@ljmu.ac.uk.

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±12kg, height 180±8cm) professional players completed a RL match after 36-h consuming a non-isocaloric high carbohydrate (n=8; 6gkgday-1) or low carbohydrate (n=8; 3gkgday-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±81mmolkg-1d.w.) were unclear. High (243±43mmolkg-1d.w.) and low carbohydrate groups (298±130mmolkg-1d.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±0.39mmoll-1 and 1.45±0.51mmoll-1, respectively), whereas differences between the 2 groups for glycerol were unclear (98.1±33.6mmoll-1 and 123.1±39.6mmoll-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.

KEYWORDS:

Competition; GPS; Metabolism; Nutrition; Physiology; Team-sport

PMID:
27134132
DOI:
10.1016/j.jsams.2016.03.008
[Indexed for MEDLINE]

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