Enhancing Physical Performance in Elite Junior Tennis Players With a Caffeinated Energy Drink

Abstract

The aim of this study was to investigate the effectiveness of a caffeinated energy drink to enhance physical performance in elite junior tennis players. In 2 different sessions separated by 1 wk, 14 young (16 ± 1 y) elite-level tennis players ingested 3 mg caffeine per kg body mass in the form of an energy drink or the same drink without caffeine (placebo). After 60 min, participants performed a handgrip-strength test, a maximal-velocity serving test, and an 8 × 15-m sprint test and then played a simulated singles match (best of 3 sets). Instantaneous running speed during the matches was assessed using global positioning (GPS) devices. Furthermore, the matches were videotaped and notated afterward. In comparison with the placebo drink, the ingestion of the caffeinated energy drink increased handgrip force by ~4.2% ± 7.2% (P = .03) in both hands, the running pace at high intensity (46.7 ± 28.5 vs 63.3 ± 27.7 m/h, P = .02), and the number of sprints (12.1 ± 1.7 vs 13.2 ± 1.7, P = .05) during the simulated match. There was a tendency for increased maximal running velocity during the sprint test (22.3 ± 2.0 vs 22.9 ± 2.1 km/h, P = .07) and higher percentage of points won on service with the caffeinated energy drink (49.7% ± 9.8% vs 56.4% ± 10.0%, P = .07) in comparison with the placebo drink. The energy drink did not improve ball velocity during the serving test (42.6 ± 4.8 vs 42.7 ± 5.0 m/s, P = .49). The preexercise ingestion of caffeinated energy drinks was effective to enhance some aspects of physical performance of elite junior tennis players.

Effects of Caffeine Supplementation on Performance in Ball Games

“…The duration and degree of the standardization protocols differed among studies. The duration whereby participants had to abstain from all dietary sources of alcohol, caffeine and other stimulants ranged from the day itself [36,40] to 24 hours [35][36][37][41][42][43][44][45], 48 hours [34,38,39,[46][47][48][49][50] and the entire study duration (2 sessions separated by 1 week) [51]. Participants were also asked to adopt a similar diet and fluid intake level the day before each experimental trial.…”

“…Participants were also asked to adopt a similar diet and fluid intake level the day before each experimental trial. Several studies also included a pre-competition meal either 2 [46] or 3 hours before each trial to mimic their habitual routines [35,36,40,44,48,49,51]. In terms of activity levels, participants were advised to avoid all strenuous exercise the day before each trial to minimize any muscle soreness and fatigue.…”

The Activity Profile of Young Tennis Athletes Playing on Clay and Hard Courts: Preliminary Data

“…The GPS underestimated the distance covered, mean speed and peak speed during court-based tennis movements and showed a low to high intraclass coefficient of correlation (ICC = 0.1 to 0.86) and a low to high coefficient of variation (CV = 3.5 to 22.8) (Duffield et al, 2010; Scott et al, 2015; Vickery et al, 2014). In a recent study, the GPS units were sensitive enough to detect locomotor activity changes in response to caffeinated energy drink ingestion in comparison to placebo (Gallo-Salazar et al, 2015). The acceleration profile was also used as a parameter of performance during the matches.…”

Ergogenic Aids and Supplements

“…Few recent studies reported an improvement in physical performance in junior tennis players [46] and adolescent basketball players [41] . Although the US Food and Drug Administration limits caffeine content in soft drinks, which are categorized as food, there is no such regulation for energy drinks, which are classified as dietary supplements.…”