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Study Title and Description

Caffeine alters anaerobic distribution and pacing during a 4000-m cycling time trial.



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 Caffeine alters anaerobic distribution and pacing during a 4000-m cycling time trial.
Author Rde A Santos,MA Kiss,MD Silva-Cavalcante,CR Correia-Oliveira,R Bertuzzi,DJ Bishop,AE Lima-Silva,
Country
Year 2013
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 purpose of the present study was to investigate the effects of caffeine ingestion on pacing strategy and energy expenditure during a 4000-m cycling time-trial (TT).
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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) In the morning of the experimental test, the participants arrived at the laboratory at 0800 h after consuming breakfast between 0700 h and 0715 h. The breakfast was standardized and consisted of 60% carbohydrate (CHO), 25% lipids and 15% protein, without caffeine. One hour before the test, the participants ingested one capsule containing caffeine or placebo, with 150 ml of water. Then, the participants rested for 45min and performed the MVCs. Thereafter, the participants started a 5-min warm-up at 100 W (90 rpm) followed by a 5-min rest and the 4000-m cycling TT. The same instructions and procedures given in the familiarization session were adopted during the experimental sessions. The HR was measured with a heart rate transmitter coupled to the gas analyzer.
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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 The HR was measured with a heart rate transmitter coupled to the gas analyzer.
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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.) Placebo vs. 5 mg/kg caffeine in a capsule taken with water
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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) The RPE, HR, [La], iEMG, PO, Pan and Paer responses during the trials were compared using a two-way analysis of variance with repeated measures, with condition (CAF vs. PLA) and distance (200, 400, 600…4000-m) as factors. When necessary, subsequent post-hoc comparisons were made using Bonferroni correction. The paired Student’s t-test was used to compare the mean values of dependent variables (RPE, HR, [La], iEMG, PO, Pan, Paer, time, anaerobic, aerobic and total work) between the CAF and PLA conditions. The effect size (ES) and the 95% of confidence interval (95% CI) were calculated to verify caffeine effects on performance, as suggested by Conger et al. [28]. The Hedges correction (Hedges’s g) was used to account for potential bias resulting from the small sample size [18]. The ES of 0.2, 0.6 and 1.2 were considered as small, moderate, and large, respectively [29,30]. Analyses were performed using SPSS (13.0) software, except for ES values, which were calculated in Comprehensive Meta analysis software. The smallest standardized change was assumed to be 0.20. Statistical significance was accepted at p<0.05.
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What conflicts of interest were reported? Not discussed.
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Refid 24058684
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What were the sources of funding? Santos RA is grateful to Coordination of Improvement of Personnel of Superior Level (CAPES) for his scholarship.
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Results & Comparisons

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