Carbohydrate-Electrolyte Feedings Improve 1 h Time Trial Cycling Performance

Jeukendrup, A. E.; Brouns, Fred; Wagenmakers, Anton J. M.; Saris, W. H. M.

doi:10.1055/s-2007-972607

Cited by 229 publications

(194 citation statements)

References 4 publications

(4 reference statements)

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“…When taken together, it is currently thought that CHO feeding during exercise may therefore augment exercise performance via multiple mechanisms consisting of muscle glycogen sparing [39], liver glycogen sparing [40] and maintenance of plasma glucose and CHO oxidation rates [41]. It is noteworthy, however, that exogenous CHO feeding during exercise also improves performance when exercise duration is <60 minutes [42], an effect that is not apparent when glucose is directly infused to the bloodstream during exercise [43]. Such data suggest that CHO feeding may also improve exercise performance via non-metabolic effects but through direct effects on the central nervous system [44].…”

Section: Is Carbohydrate Still King?mentioning

confidence: 99%

New strategies in sport nutrition to increase exercise performance

Hamilton

Philp

et al. 2016

Free Radical Biology and Medicine

173

118

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Despite over 50 years of research, the field of sports nutrition continues to grow at a rapid rate. Whilst the traditional research focus was one that centred on strategies to maximize competition performance, emerging data in the last decade has demonstrated how both macronutrient and micronutrient availability can play a prominent role in regulating those cell signalling pathways that modulate skeletal muscle adaptations to endurance and resistance training. Nonetheless, in the context of exercise performance, it is clear that carbohydrate (but not fat) still remains king and that carefully chosen ergogenic aids (e.g. caffeine, creatine, sodium bicarbonate, beta-alanine, nitrates) can all promote performance in the correct exercise setting. In relation to exercise training, however, it is now thought that strategic periods of reduced carbohydrate and elevated dietary protein intake may enhance training adaptations whereas high carbohydrate availability and antioxidant supplementation may actually attenuate training adaptation. Emerging evidence also suggests that vitamin D may play a regulatory role in muscle regeneration and subsequent hypertrophy following damaging forms of exercise. Finally, novel compounds (albeit largely examined in rodent models) such as epicatechins, nicotinamide riboside, resveratrol, β-hydroxy β-methylbutyrate, phosphatidic acid and ursolic acid may also promote or attenuate skeletal muscle adaptations to endurance and strength training. When taken together, it is clear that sports nutrition is very much at the heart of the Olympic motto, Citius, Altius, Fortius (faster, higher, stronger).

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Section: Is Carbohydrate Still King?mentioning

confidence: 99%

New strategies in sport nutrition to increase exercise performance

Hamilton

Philp

et al. 2016

Free Radical Biology and Medicine

173

118

View full text Add to dashboard Cite

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“…However, the literature is equivocal on whether CHO ingestion improves performance during shorter duration (≤ 1 hours) endurance exercise, with some studies showing improvements (2), and others not (21). Potential improvements cannot be only explained by sparing of glycogen stores (21,34) and exogenous CHO availability during the first hour of exercise (23). Thus, any performance benefits may be due to a central effect.…”

Section: Introductionmentioning

confidence: 99%

Mouth Rinsing With Carbohydrate Solutions at the Postprandial State Fail to Improve Performance During Simulated Cycling Time Trials

Ispoglou¹,

OʼKelly²,

Angelopoulou³

et al. 2015

Journal of Strength and Conditioning Research

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Mouth-rinsing with carbohydrate solutions during cycling time trials results in performance enhancements, however the majority of studies have utilised ~6% carbohydrate solutions.Therefore, the purpose of this study was to compare the effectiveness of mouth-rinsing with 4%, 6%, and 8% carbohydrate (CHO) solutions on 1-h simulated cycling time trial performance. On four occasions, seven trained male cyclists completed at the postprandial period, a set amount of work as fast as possible in a randomised, counterbalanced order. The subjects mouth rinsed for 5-s, upon completion of each 12.5% of the trial, with 25 mL of a non-CHO placebo, 4%, 6%, and 8% CHO solutions. No additional fluids were consumed during the time trial. Heart rate (HR), ratings of perceived exertion (RPE), thirst (TH) and subjective feelings (SF) were recorded after each rinse. Further, blood samples were drawn every 25% of the trial to measure blood glucose (BG) and blood lactate (BG) concentrations, whilst whole body carbohydrate oxidation was monitored continuously. Time to completion was not significant between conditions with the placebo, 4%, 6%, and 8% conditions completing the trials in 62.0 ± 3.0, 62.8 ± 4.0, 63.4 ± 3.4, and 63 ±4.0 minutes respectively. There were no significant differences between conditions in any of the variables mentioned above however significant time effects were observed for HR, RPE, TH, and SF. Post-hoc analysis showed that TH and SF of subjects in the CHO conditions but not in the placebo were significantly increased by completion of the time trial. In conclusion, mouth-rinsing with CHO solutions did not impact 1-h cycling performance in the postprandial period and in the absence of fluid intake. Our findings suggest that there is scope for further research to explore the activation regions of the brain and whether they are receptive to CHO dose, before specific recommendations for athletic populations are established. Consequently mouth-rinsing as a practical strategy for coaches and athletes is questionable under specific 3 conditions and should be carefully considered before its inclusion. The emphasis should be focused on appropriate dietary and fluid strategies during training and competition.

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“…Unlike long-chain fatty acids, medium-chain fatty acids (MCFA) can be absorbed more rapidly and directly from the intestinal lumen (5, 13), and their entry into mitochondria does not appear to be rate limited by the acyl-carnitine transfer system to the extent of long chain fatty acids during high-intensity exercise (33). Therefore, ingestion of MCFAs during exercise has the potential to enhance performance by elevating plasma FFA concentrations and sparing muscle glycogen (17,35,36).In trials feeding 25-30 g MCT suspensions, the oxidation of MCFA reached 30% compared with 70% oxidation when coingested with carbohydrate (CHO); plasma FFA and ketone concentrations were elevated, but no overall change in total lipid or carbohydrate oxidation was observed (8,19,20). In contrast, 86 g MCT coingested with CHO has resulted in elevation of serum FFA concentration, reduced reliance on endogenous carbohydrate, and performance enhancement (2.5% decrease in 40-km time-trial time) relative to CHO-only ingestion with no reports of gastrointestinal distress (35).…”

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confidence: 99%

Attenuated gastric distress but no benefit to performance with adaptation to octanoate-rich esterified oils in well-trained male cyclists

Thorburn

Vistisen²,

Thorp³

et al. 2006

Journal of Applied Physiology

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lands. Attenuated gastric distress but no benefit to performance with adaptation to octanoate-rich esterified oils in well-trained male cyclists. J Appl Physiol 101: [1733][1734][1735][1736][1737][1738][1739][1740][1741][1742][1743] 2006. First published July 13, 2006; doi:10.1152/japplphysiol.00393.2006.-We investigated the effects of modifying a normal dietary fatty acid composition and ingestion of high-fat exercise supplements on gastrointestinal distress, substrate oxidation, and endurance cycling performance. Nine welltrained male cyclists completed a randomized triple-crossover comprising a 2-wk diet high in octanoate-rich esterified oil (MCFA) or twice long-chain fatty acids (LCFA). Following the diets, participants performed 3-h of cycling at 50% of peak power followed by 10 maximal sprints while ingesting either 1) a carbohydrate (CHO)ϩMCFA-rich oil emulsion after the 2-wk MCFA-rich dietary condition (MC-MC, Intervention) and 2) after one of the LCFA-rich dietary conditions (LC-MC, Placebo) or 3) CHO only following a LCFA-rich diet (LC-CHO, Control). During the 3-h ride MCFAadaptation decreased octanoic-acid oxidation by 24% (90% confidence interval: 14 -34%). The CHOϩMCFA-rich oil emulsion reduced endogenous fat oxidation by 61% (33-89%) and 110% (89 -131%) in the MC-MC and LC-MC conditions, respectively, and MCFA-adaptation reduced endogenous-carbohydrate oxidation by 10% (Ϫ3-23%). MCFA-adaptation attenuated gastrointestinal distress and nausea during the sprints, but the effect of the oil emulsion was to lower sprint power by 10.9% (7.7-14.1%) in the LC-MC condition and by 7.1% (5.7-8.5%) in the MC-MC condition, relative to the LC-CHO control; every one unit increase in nausea decreased mean power by 6.0 W (3.2-8.8 W). We conclude that despite some attenuation of endogenous-carbohydrate oxidation and gastric distress following adaptation to a MCFA-rich diet, repeat sprint performance was substantially impaired in response to the ingestion of a CHOϩMCFA-rich oil emulsion. medium-chain fatty acids; structured triacylglycerols; dietary adaptation; supplementation THE FINITE AVAILABILITY of endogenous glycogen as an energy substrate contributes to the development of fatigue and is therefore a limiting factor in athletic performance during prolonged strenuous exercise (23). An increase in plasma free fatty acid (FFA) and fat oxidation has been shown to spare endogenous glycogen, most reliably via fat infusion studies (38). However, fat infusion during racing conditions is not feasible, and long-chain triglyceride ingestion before or during exercise has not been shown to enhance performance (14,32,40). More recently, interest has focused on the ingestion of medium-chain triglycerides (MCTs). Unlike long-chain fatty acids, medium-chain fatty acids (MCFA) can be absorbed more rapidly and directly from the intestinal lumen (5, 13), and their entry into mitochondria does not appear to be rate limited by the acyl-carnitine transfer system to the extent of long chain fatty acids during high-intensity exercise ...

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Carbohydrate-Electrolyte Feedings Improve 1 h Time Trial Cycling Performance

Cited by 229 publications

References 4 publications

New strategies in sport nutrition to increase exercise performance

New strategies in sport nutrition to increase exercise performance

Mouth Rinsing With Carbohydrate Solutions at the Postprandial State Fail to Improve Performance During Simulated Cycling Time Trials

Attenuated gastric distress but no benefit to performance with adaptation to octanoate-rich esterified oils in well-trained male cyclists

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