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Study Title and Description

The influence of caffeine and carbohydrate coingestion on simulated soccer performance.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on cardiovascular outcomes?
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Primary Publication Information
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TitleData
Title The influence of caffeine and carbohydrate coingestion on simulated soccer performance.
Author N Gant,A Ali,A Foskett,
Country
Year 2010
Numbers

Secondary Publication Information
There are currently no secondary publications defined for this study.


Extraction Form: Cardiovascular Design
Design Details
Question... Follow Up Answer Follow-up Answer
What outcome is being evaluated in this paper? Cardiovascular
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What is the objective of the study (as reported by the authors)? The aim of this study was to examine the influence of adding a moderate dose of caffeine to a carbohydrate solution during prolonged soccer activity. Fifteen male soccer players performed two 90-min intermittent shuttle-running trials.
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Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) Participants: Fifteen male Premier-grade soccer players (age 21.3 ± 3 years, body mass 72 ± 8 kg) gave informed written consent before participating in this study, which received local ethical clearance. Participants were required to be 16–30 years old and playing in the regional Premier Division during the season of the trials. Experimental design: Participants performed two experimental trials separated by 7 days. To eliminate any trial-order effects players were assigned randomly in a double-blind crossover design to trials involving the ingestion of a 6% CHOelectrolyte solution with (CAF) or without (CON) the addition of 160 mg/L of caffeine. Participants abstained from caffeine, alcohol, and strenuous activity and recorded their dietary intake for 48 hr before the main experimental trials. This diet was then replicated before the second experimental trial. Figure 1 shows a schematic representation of the main experimental protocol. Participants arrived at the laboratory at a standardized time of the day, approximately 3 hr after a meal, at which time a urine sample was collected to measure urine osmolality (Wescor 5500 vapor pressure osmometer) and nude body mass was determined before participants ingested a volume of each solution equivalent to 8 ml/kg body mass 1 hr before exercise. The intermittent running protocol used in the main experimental trials was the LIST (Nicholas et al., 2000). Participants completed 90 min of this LIST protocol; the 15-min bouts of exercise were separated by 4-min rest periods. Before beginning exercise, and during the rest periods, participants performed a countermovement jump (CMJ) on an electronic mat (Just Jump System 7610, Perform Better, USA) and one attempt of the LSPT. The LSPT has been shown to be a valid and reliable indicator of soccer-skill performance, especially in players of high ability (Ali, Williams, Hulse, et al., 2007). After these tests participants rapidly ingested (<120 s) 3 ml/kg body mass of the appropriate test drink before the next phase of the LIST protocol. Heart rate was monitored every 15 s during exercise using short-range telemetry (Polar Model 610, Kempele, Finland), and the mean was recorded for each 15-min exercise period. On completion of the exercise protocol, each participant emptied his bladder, with a sample retained for later analysis of urine caffeine concentration, and nude body mass was measured.
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How many outcome-specific endpoints are evaluated? 1
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Heart rate
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List additional health endpoints (separately). 2
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List additional health endpoints (separately).3
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List additional health endpoints (separately).4
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List additional health endpoints (separately).5
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List additional health endpoints (separately).6
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Clinical, physiological, other Physiological
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What is the study design? Controlled Trial
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Randomized or Non-Randomized? RCT
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What were the diagnostics or methods used to measure the outcome? Objective
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Optional: Name of Method or short description Heart rate was monitored every 15 s during exercise using short-range telemetry (Polar Model 610, Kempele, Finland), and the mean was recorded for each 15-min exercise period.
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Caffeine (general) Caffeine (general)
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Coffee, Chocolate, energy drink, gum, medicine/supplement, soda, tea, other?
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Measured or self reported? Measured
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Children, adolescents, adults, or pregnant included? Adults
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) Control (no caffeine) carbohydrate drink. This was a cross-over study. Participants completed trials with 7-days in between trials.
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What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) To detect systematic bias in comparisons over time, two-factor (Treatment x Time) general linear models with repeated measures on both factors were used to analyze main effects and the interaction of factors. Significant interactions were explored using the Holm–Bonferroni stepwise method (Atkinson, 2002). For single comparisons between normally distributed data, paired Student’s t tests (two-tailed) were used to examine bias between treatments or times.
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What conflicts of interest were reported? Not discussed.
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Refid 20601736
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What were the sources of funding? This study was supported by a research grant from Glaxo- SmithKline (UK).
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Results & Comparisons

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