Effects of pre-exercise ingestion of a carbohydrate-electrolyte gel on cycling performance
© Willems et al; licensee BioMed Central Ltd. 2011
Published: 7 November 2011
Exercise performance can benefit from pre-exercise ingestion of carbohydrate-electrolyte drinks. Carbohydrate-electrolyte gels may provide a convenient and effective energy source for subsequent exercise bouts, but supportive evidence needs to be provided. We examined the effect of pre-exercise ingestion of a commercial carbohydrate-electrolyte gel on cycling performance.
Following an overnight fast, healthy males (n = 12, age: 24 ± 7 yr, height: 181 ± 6 cm, body mass: 78.1 ± 9.4 kg, VO2max: 47.6 ± 7.1 mL·kg-1·min-1, Wmax: 316 ± 51 W) cycled steady state (40 min, SS1, 56 ± 4%Wmax, SRM Ergometer) followed by a time trial (15 min, TT1,Wattbike cycle ergometer), a 2 hour passive recovery, and cycled steady state (20 min, SS2, power equal to SS1) followed by a time trial (15 min, TT2). Participants ingested either placebo (P, low-caloric gel, equal in flavour) or Maxifuel’s Viper® Active Gel (V, 65 gram equal to one gel) (Maxinutrition Ltd, Hemel Hempstead, UK), 15 min pre-SS1 (+250 ml water), 0 hr post-TT1 (+750 ml water), 1 hr post-TT1 (+250 ml water), and 15 min pre-SS2 (+250 ml water). Maxifuel’s Viper® Active Gel contains 22 g maltodextrin, 11.2 g sucrose, 1.5 g dextrose, 0.8 g fructose and 0.1g sodium per 100g). Experimental design was double-blind and randomized. Carbohydrate oxidation was calculated with stoichiometric equations from Jeukendrup & Wallis. Two-way ANOVA with post-hoc t-tests were used for analysis with significance accepted at p < 0.05.
During SS1, heart rate, oxygen uptake, respiratory exchange ratio, rating of perceived exertion, plasma lactate and carbohydrate oxidation were not different between conditions. There was a trend for blood glucose (mmol·L-1) with Viper during SS1 to be higher at 0 min (P: 4.26 ± 0.21, V: 6.36 ± 0.76) and 10 min (P: 3.89 ± 0.37, V: 4.98 ± 0.70), and lower at 20 min (P: 3.89 ± 0.47, V: 3.12 ± 0.69) and 30 min (P: 3.92 ± 0.45, V: 3.12 ± 0.69). During SS2, heart rate, oxygen uptake, rating of perceived exertion and plasma lactate were not different between conditions. Blood glucose (in mmol·L-1) with Viper during SS2 was higher at 0 min (P: 3.80 ± 0.40, V: 5.33 ± 0.77) and 10 min (P: 3.56 ± 0.40, V: 4.10 ± 0.55). Respiratory exchange ratio was higher during SS2 for Viper at 5 min (P: 0.90 ± 0.09, V: 0.99 ± 0.08). Carbohydrate oxidation (g·min-1) during SS2 was higher with Viper at 5 min (P: 2.11 ± 0.84, V: 2.97 ± 0.71). Cycling distance during TT1 and TT2 was 3.1% (P: 9467 ± 963 m, V: 9741 ± 817 m) and 3.4% (P: 9375 ± 943 m, V: 9667 ± 746 m) higher with the carbohydrate-electrolyte gel ingestion.
It is concluded that pre-exercise ingestion of a 65 gram commercial carbohydrate-electrolyte gel with multiple carbohydrates benefits cycling performance. In addition, the ingestion of the carbohydrate-electrolyte gel during recovery enhanced subsequent cycling performance. The consumption of commercial carbohydrate-electrolyte gels with different carbohydrates may be beneficial for athletes with multiple daily training sessions.
Supplements were provided by Maxinutrition Ltd (Hertfordshire, UK). After study completion, funding for conference attendance was obtained from Maxinutrition Ltd (Hertfordshire, UK).
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