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Neil D. Clarke and Michael J. Duncan

Purpose:

To investigate the effect of ingesting carbohydrate and caffeine solutions on measures that are central to success in badminton.

Methods:

Twelve male badminton players performed a badminton serve-accuracy test, coincidence-anticipation timing (CAT), and a choice reaction-time sprint test 60 min before exercise. Participants then consumed 7 mL/kg body mass of either water (PLA), 6.4% carbohydrate solution (CHO), a solution containing a caffeine dose of 4 mg/kg, or 6.4% carbohydrate and 4 mg/kg caffeine (C+C). All solutions were flavored with orange-flavored concentrate. During the 33-min fatigue protocol, participants were provided with an additional 3 mL/kg body mass of solution, which was ingested before the end of the protocol. As soon as the 33-min fatigue protocol was completed, all measures were recorded again.

Results:

Short-serve accuracy was improved after the ingestion of CHO and C+C compared with PLA (P = .001, ηp 2 = .50). Long-serve accuracy was improved after the ingestion of C+C compared with PLA (P < .001, ηp 2 = .53). Absolute error in CAT demonstrated smaller deteriorations after the ingestion of C+C compared with PLA (P < .05; slow, ηp 2 = .41; fast, ηp 2 = .31). Choice reaction time improved in all trials with the exception of PLA, which demonstrated a reduction (P < .001, ηp 2 = .85), although C+C was faster than all trials (P < .001, ηp 2 = .76).

Conclusion:

These findings suggest that the ingestion of a caffeinated carbohydrate solution before and during a badminton match can maintain serve accuracy, anticipation timing, and sprinting actions around the court.

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Neil D. Clarke, Darren L. Richardson, James Thie and Richard Taylor

Context : Caffeine, often in the form of coffee, is frequently used as a supplement by athletes in an attempt to facilitate improved performance during exercise. Purpose: To investigate the effectiveness of coffee ingestion as an ergogenic aid prior to a 1-mile (1609 m) race. Methods: In a double-blind, randomized, cross-over, and placebo-controlled design, 13 trained male runners completed a 1-mile race 60 minutes following the ingestion of 0.09 g·kg−1 coffee (COF), 0.09 g·kg−1 decaffeinated coffee (DEC), or a placebo (PLA). All trials were dissolved in 300 mL of hot water. Results: The race completion time was 1.3% faster following the ingestion of COF (04:35.37 [00:10.51] min:s.ms) compared with DEC (04:39.14 [00:11.21] min:s.ms; P = .018; 95% confidence interval [CI], −0.11 to −0.01; d = 0.32) and 1.9% faster compared with PLA (04:41.00 [00:09.57] min:s.ms; P = .006; 95% CI, −0.15 to −0.03; d = 0.51). A large trial and time interaction for salivary caffeine concentration was observed (P < .001; ηp2=.69), with a very large increase (6.40 [1.57] μg·mL−1; 95% CI, 5.5–7.3; d = 3.86) following the ingestion of COF. However, only a trivial difference between DEC and PLA was observed (P = .602; 95% CI, −0.09 to 0.03; d = 0.17). Furthermore, only trivial differences were observed for blood glucose (P = .839; ηp2=.02) and lactate (P = .096; ηp2=.18) and maximal heart rate (P = .286; ηp2=.13) between trials. Conclusions: The results of this study show that 60 minutes after ingesting 0.09 g·kg−1 of caffeinated coffee, 1-mile race performance was enhanced by 1.9% and 1.3% compared with placebo and decaffeinated coffee, respectively, in trained male runners.

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Matthew Ellis, Mark Noon, Tony Myers and Neil Clarke

Context: High doses of ∼6 mg·kg−1 body mass have improved performance during intermittent running, jumping, and agility protocols. However, there are sparse data on low doses of caffeine, especially in elite adolescent soccer players. Methods: A total of 15 elite youth soccer players (177.3 [4.8] cm, 66.9 [7.9] kg, and 16 [1] y) participated in the study, consuming 1, 2, or 3 mg·kg−1 caffeine in a gelatin capsule or a 2-mg·kg−1 placebo in a single-blind, randomized, crossover study design. Testing consisted of a 20-m sprint, arrowhead agility (change of direction [CoD] right or left), countermovement jump (CMJ), and Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IR1). Postexercise CMJ performance was assessed as participants exited the Yo-Yo IR1. Data were analyzed using a Bayesian multilevel regression model to provide explained variance and probabilities of improvement (P = %). Results: Compared with placebo, 3 mg·kg−1 caffeine presented the highest probabilities of change across a range of tests (mean [SD], P = %). Times for 20-m sprint were 3.15 (0.10) s vs 3.18 (0.09) s (P = 73%), CoD-right times were 8.43 (0.24) s vs 8.55 (0.25) s (P = 99%), CoD-left times were 8.44 (0.22) s vs 8.52 (0.18) s (P = 85%), Yo-Yo IR1 distance was 2440 (531) m vs 2308 (540) m (P = 15%), and preexercise CMJ height was 41.6 (7.2) cm vs 38 (8.5) cm (P = 96%). Postexercise CMJ was higher with 3 mg·kg−1 than with placebo (42.3 [8] cm vs 36.6 [8] cm; P = 100%). Doses of 1 or 2 mg·kg−1 caffeine also demonstrated the ability to enhance performance but were task dependent. Conclusion: Low doses of caffeine improve performance but are dose and task dependent. A dose of 3 mg·kg−1 caffeine improved performance across the majority of tests with potential to further improve postexercise CMJ height.