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Date of Graduation
Master of Science (MS)
Department of Kinesiology
Christopher J. Womack
Michael J. Saunders
Purpose: This study examined the efficacy of caffeine supplementation on tennis performance in male and female collegiate tennis players and whether a polymorphism of the CYP1A2 gene influenced the ergogenic response to caffeine. Methods: Eighteen collegiate tennis players (9 male; 9 female) completed two separate trials. Each test occurred one hour after the administration of either 6 mg/kg of caffeine or a placebo, administered in double-blind fashion. The treadmill portion was comprised of 15 minutes at a velocity corresponding with 50% VO2max followed by 30 minutes of intermittent sprints (5 seconds at 80% VO2max, 15 seconds at 50% VO2max). 90 second resting periods were administered after the 18th sprint and every twelve sprints thereafter, mirroring the discontinuous nature of tennis. RPE and HR was taken before each 90 second resting period. 120 seconds following the treadmill test, the tennis skills test was administered. A 6-ball drill comprised with 4 groundstrokes, 1 approach shot and 1 volley were fed, followed by a 20 second resting period. The 6-ball drill was repeated 6 times, and every 2 sessions were followed by a 90 second break. Nine full sessions were performed with RPE and HR recorded prior to resting periods. Subjects completed these methods for both treatments, in a randomly counterbalanced, double-blind protocol. DNA was obtained from whole blood samples and analyzed for presence of the C variant using polymerase chain reaction with allele-specific primers. Subjects were classified as AA homozygotes (N=7) or C allele carriers (N=9). Results: Caffeine significantly (P=0.029) improved performance during the Tennis Skills test. There was no genotype effect (P=.454), regardless of gender. There was no main effect for treatment on RPE during the treadmill portion of the test and no significant main effects or interaction effects for RPE following ingestion of caffeine during the Tennis Skills Test. A significant gender effect existed during the treadmill portion of the test (P=0.020) and Tennis Skills test (P=0.027) for RPE with women exhibiting a lower RPE men. Furthermore, on average, caffeine elevated peak HR in AA homozygotes and lowered peak HR for C allele carriers. Conclusion: Caffeine supplementation positively impacts tennis performance regardless of genotype.
Klein, Courtney, "The efficacy of caffeine supplementation in collegiate tennis players and the magnitude of improvement in tennis skill mediated by caffeine influenced by a polymorphism of the CYP1A2 gene" (2010). Masters Theses. 441.