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Study Title and Description

Effect of caffeine as an ergogenic aid during anaerobic exercise performance in caffeine naïve collegiate football players.



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 Effect of caffeine as an ergogenic aid during anaerobic exercise performance in caffeine naïve collegiate football players.
Author K Woolf,WK Bidwell,AG Carlson,
Country
Year 2009
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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)? This study examined the effect of caffeine (5 mg/kg body weight) vs. placebo on performance-based anaerobic exercise tests used during the National Football League (NFL) Combine.
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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) Experimental approach to the problem: The primary purpose of this study was to examine the effects of a moderate dose of caffeine during field-type exercises in highly trained collegiate male football players. A randomized, double-blind crossover study examined the impact of a moderate dose of caffeine (5 mg/kg BW) on anaerobic performance in male football players, 18 to 23 years of age. Our primary null hypothesis was that the ingestion of a beverage with a 5.0 mg/kg BW dose of caffeine would not significantly improve exercise performance in collegiate male football players using the 185 or 225 lb bench press, a 40-yard dash, and a 20-yard shuttle. Our secondary null hypothesis was that the ingestion of a beverage with 5.0 mg/kg BW dose of caffeine would not alter heart rate (HR), blood pressure (BP), or Borg’s rating of perceived exertion (RPE). Subjects: Recruitment began in November of 2004 and involved both oral communication as well as a recruitment flyer distributed to local community colleges and athletic facilities. Athletes were also recruited from Athletes’ Performance, a state-of-the-art facility that trains elite and professional athletes. Participants were eligible if they fit the following inclusion criteria: played collegiate football during the past season. To assess usual intake of caffeine, participants completed the Arizona Food Frequency Questionnaire (AFFQ) (University of Arizona, Tucson, AZ). Participants were given written and oral instructions on how to complete the questionnaire. The AFFQs were analyzed by the NCS OpScan 5 (Al-Bassam International Company, Al-Khobar, Saudi Arabia). Typical dietary caffeine intake was 16 +/- 20 (range, 0–81) mg/day. Sixteen participants consumed less than 50 mg/day, and 1 participant consumed greater than 50 mg/day (Table 1). Participants: Participants reported to Athletes’ Performance twice, separated by 1 week, after an 8- to 12-hour fast and abstaining from caffeinated products for 48 hours. HR and BP were measured upon arrival to the facility. A Polar heart rate monitor (Polar T1 model CEO 537, Lake Success, NY) was used to monitor HR, and a professional stethoscope (Adscope series 601, Miami, FL) and sphygmomanometer (Moore Medical, New Britain, CT) were used to monitor BP. The participants then consumed a beverage with caffeine (caffeine, 5.0 mg/kg BW; carbohydrate (CHO), 0.125 g/kg BW) or without caffeine (placebo; CHO, 0.125 g/kg BW) and ate A meal 15 minutes later (Table 1). Each participant consumed the same meal during each of the test days. Sixty minutes after consuming the beverage, participants performed 3 exercise tests: a 40-yard dash test, 20-yard shuttle, and a bench press (Olympic bar) with repetitions to fatigue using 185 or 225 lb. The lower weight (185 lb) was used for the participants who could not press 225 lb. Postexercise HR and BP were measured immediately after the final exercise test.
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How many outcome-specific endpoints are evaluated? 2
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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 Blood pressure
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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 Polar heart rate monitor (Polar T1 model CEO 537, Lake Success, NY) was used to monitor HR, and a professional stethoscope (Adscope series 601, Miami, FL) and sphygmomanometer (Moore Medical, New Britain, CT) were used to monitor BP.
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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 beverage with no caffeine; also pre-exercise HR and BP were taken for subjects.
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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) Descriptive statistics (age, height, weight, BMI) were expressed as mean 6 SD. Normality of data was assessed using histograms and the Kolmogorov-Smirnov test statistic. Tests for normality were met for the 40-yard dash, 20- yard shuttle, RPE, and HR. Before analysis, the bench press data were transformed using the logarithm. Mean and SD values in the tables are the untransformed values. Paired t-tests using the Statistical Package for Social Sciences (SPSS, version 14.0, 2005, Chicago, IL) determined the independent effects of caffeine vs. no caffeine on exercise performance during the bench press, 40-yard dash, and 20-yard shuttle. A 2-way repeated-measures analysis of variation + Bonferroni post hoc test was used to examine significant differences in HR and systolic (S)BP for time, treatment, and their interaction. A Wilcoxon signed rank test was used to test for differences for the diastolic (D)BP data.
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What conflicts of interest were reported? Conflicts were not mentioned in the paper.
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Refid 19620930
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What were the sources of funding? Grant Support: Experimental and Applied Science, Inc.
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