Metabolic and performance effects of raisins versus sports gel as pre-exercise feedings in cyclists.

Department of Exercise and Nutritional Sciences, San Diego State University, San Diego, California 92182, USA.
The Journal of Strength and Conditioning Research (Impact Factor: 1.8). 12/2007; 21(4):1204-7. DOI: 10.1519/R-21226.1
Source: PubMed

ABSTRACT Research suggests that pre-exercise sources of dietary carbohydrate with varying glycemic indexes may differentially affect metabolism and endurance. This study was designed to examine potential differences in metabolism and cycling performance after consumption of moderate glycemic raisins vs. a high glycemic commercial sports gel. Eight endurance-trained male (n = 4) and female (n = 4) cyclists 30 +/- 5 years of age completed 2 trials in random order. Subjects were fed 1 g carbohydrate per kilogram body weight from either raisins or sports gel 45 minutes prior to exercise on a cycle ergometer at 70% V(.-)O2max. After 45 minutes of submaximal exercise, subjects completed a 15-minute performance trial. Blood was collected prior to the exercise bout, as well as after the 45th minute of exercise, to determine serum concentrations of glucose, insulin, lactate, free fatty acids (FFAs), triglycerides, and beta-hydroxybutyrate. Performance was not different (p > 0.05) between the raisin (189.5 +/- 69.9 kJ) and gel (188.0 +/- 64.8 kJ) trials. Prior to exercise, serum concentrations of glucose and other fuel substrates did not differ between trials; however, insulin was higher (p < 0.05) for the gel (110.0 +/- 70.4 microU x ml(-1)) vs. raisin trial (61.4 +/- 37.4 microU x ml(-1)). After 45 minutes of exercise, insulin decreased to 14.2 +/- 6.2 microU x ml(-1) and 13.3 +/- 18.9 microU x ml(-1) for gel and raisin trials, respectively. The FFA concentration increased (+0.2 +/- 0.1 mmol x L(-1)) significantly (p < 0.05) during the raisin trial. Overall, minor differences in metabolism and no difference in performance were detected between the trials. Raisins appear to be a cost-effective source of carbohydrate for pre-exercise feeding in comparison to sports gel for short-term exercise bouts.

1 Bookmark
  • [Show abstract] [Hide abstract]
    ABSTRACT: Country-of-origin (COO) image may imbue product beliefs, just as beliefs about a travel destination can form from destination image. As COO and destination image both concern belief formations from images, we meld these research streams to investigate the influence of destination image on beliefs of and preference for the destination’s local products. We posit that consumers may non-consciously form a COO image from destination image, which in turn influences product preference. Consumers in China (n=226) and Chinese tourists in Australia (n=235) self-reported their perceptions of Australia as a tour destination and of Australian wine. The results show that destination image positively influences product beliefs with both samples, but the influence is stronger with Chinese consumers who are unfamiliar with Australia. Destination image influences product preference indirectly via product beliefs. A key managerial implication is that exporters and tourism authorities should cooperate to harness a country’s destination image for exports.
    Australasian Marketing Journal (AMJ) 01/2011; 19(1):7-13.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective: The aim of the study was to determine the feeding habits of the cyclists of the Spanish mountain bike (MTB) national team. Method: Forty cyclists were distributed in two categories according to time spent in training and competing category (25 Cadet/junior (C/J) -16.68 ± 0.99 years-, and 15 Under-23/elite (U23/E) -25.33 ± 4.25 years-. All the subjects completed a specific questionnaire about their feeding habits. Descriptive and contrast (Mann-Whitney) statistic was carried out in the 2 studied groups. Results: Seventy Six per cent of the subjects of the C/J group showed incorrect feeding habit, and significantly less (36%) than the U23/E showed also incorrect patterns (p = 0.003). Seventy six per cent of the C/J and 60% of the U23/E do 3 intakes/day (p = 0.348), while 20% of C/J and 26.7% of the U23/E do 5 intakes/day. Sixty four per cent of the C/J and 26% of the U23/E eat between meals (p = 0.024). Also, 56% of C/J group and 20% of the U23/E group eat "fast food" (p = 0.028). Conclusions: Feeding habits of the C/J cyclists of the Spanish national team are considered inadequate, being significantly better for the U23/E group, although also in this older group there are basic aspects to improve.
    Nutricion hospitalaria: organo oficial de la Sociedad Espanola de Nutricion Parenteral y Enteral 02/2010; 25(1):85-90. · 1.31 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Endurance athletes rarely compete in the fasted state, as this may compromise fuel stores. Thus, the timing and composition of the pre-exercise meal is a significant consideration for optimizing metabolism and subsequent endurance performance. Carbohydrate feedings prior to endurance exercise are common and have generally been shown to enhance performance, despite increasing insulin levels and reducing fat oxidation. These metabolic effects may be attenuated by consuming low glycemic index carbohydrates and/or modified starches before exercise. High fat meals seem to have beneficial metabolic effects (e.g., increasing fat oxidation and possibly sparing muscle glycogen). However, these effects do not necessarily translate into enhanced performance. Relatively little research has examined the effects of a pre-exercise high protein meal on subsequent performance, but there is some evidence to suggest enhanced pre-exercise glycogen synthesis and benefits to metabolism during exercise. Finally, various supplements (i.e., caffeine and beetroot juice) also warrant possible inclusion into pre-race nutrition for endurance athletes. Ultimately, further research is needed to optimize pre-exercise nutritional strategies for endurance performance.
    Nutrients 01/2014; 6(5):1782-1808. · 3.15 Impact Factor