Carbohydrate-Supplement Form and Exercise Performance

Abstract

Numerous studies have shown that ingesting carbohydrate in the form of a drink can improve exercise performance by maintaining blood glucose levels and sparing endogenous glycogen stores. The effectiveness of carbohydrate gels or jellybeans in improving endurance performance has not been examined. On 4 separate days and 1-2 hr after a standardized meal, 16 male (8; 35.8 +/- 2.5 yr) and female (8; 32.4 +/- 2.4 yr) athletes cycled at 75% VO(2peak) for 80 min followed by a 10-km time trial. Participants consumed isocaloric (0.6 g of carbohydrate per kg per hour) amounts of randomly assigned sports beans, sports drink, gel, or water only, before, during, and after exercise. Blood glucose concentrations were similar at rest between treatments and decreased significantly during exercise with the water trial only. Blood glucose concentrations for all carbohydrate supplements were significantly, p < .05, higher than water during the 80-min exercise bout and during the time trial (5.7 +/- 0.2 mmol/L for sports beans, 5.6 +/- 0.2 mmol/L for sports drink, 5.7 +/- 0.3 mmol/L for gel, and 4.6 +/- 0.3 mmol/L for water). There were no significant differences in blood glucose between carbohydrate treatments. The 10-km time trials using all 3 carbohydrate treatments were significantly faster (17.2 +/- 0.6 min for sports beans, 17.3 +/- 0.6 min for sports drink, and 17.3 +/- 0.6 min for gel) than water (17.8 +/- 0.7 min). All carbohydrate-supplement types were equally effective in maintaining blood glucose levels during exercise and improving exercise performance compared with water only.

Carbohydrate Intake in Form of Gel Is Associated With Increased Gastrointestinal Distress but Not With Performance Differences Compared With Liquid Carbohydrate Ingestion During Simulated Long-Distance Triathlon

“…Our results obtained during prolonged exercise (300 min) complement previous results during shorter exercise durations, according to which CHO administration in form of GEL was not associated with differences in performance when compared with CHO administration in form of LIQ. Campbell et al (2008) reported that CHO administration in form of GEL resulted in a 2.8% improvement in 10-km cycling time trial performance compared with water, but no performance benefit was observed when compared with administration of the same amount of CHO in form of LIQ or sport beans (Campbell et al, 2008). …”

“…Pfeiffer et al (2010) reported no difference in CHO oxidation when cyclists exercising at 59% peak oxygen consumption (V O 2 peak ) for 180 min were given 108 g•h -1 of CHO either in the form of GEL or from a liquid source. Likewise, the administration of GEL was found to be equally effective in maintaining blood glucose and improving performance in cyclists compared with an isocaloric sports drink (Campbell et al, 2008). In contrast, Burke et al (2005) reported no significant performance benefit of GEL compared with water only during a half-marathon run (Burke et al, 2005).…”

Using the Placebo Effect to Isolate Control Mechanisms of Athletic Performance: A Research Protocol

“…39 The mode of administration of a CHO supplement was analyzed for its influence on the metabolic response and exercise performance and researchers found no difference in the beneficial effects of sport beans, sport drink or gel. 40 These results however could be due to a ceiling effect, meaning that the administered dose of CHO reached the level above which variance in endurance performance is no longer measurable, thus masking any potential influence of perceptual attributes. Including placebo groups receiving the same supplements matched for flavour and appearance without CHO could have revealed any potential differences.…”

O uso do carboidrato antes da atividade física como recurso ergogênico: revisão sistemática

“…A suplementação com carboidratos pode ser realizada de diferentes formas físicas, líquidas como bebidas esportivas (sport drinks), semissólido como géis e sólidos como barras de cereais ou as balas energéticas (jelly beans) 43,44 .…”

“…Estudo realizado por Campbell et al 44 , com ciclistas e triatletas (n=16) em bicicleta ergométrica, mostraram que entre as formas de carboidratos (bebida esportiva, gel e balas energéticas) não houve distinção nos níveis plasmáticos de glicose ou mesmo uma melhor performance entre as formas estudadas, porém em relação ao placebo (água) houve diferença significativa nos dois parâmetros.…”