Effects of sports drinks on the maintenance of physical performance during 3 tennis matches: a randomized controlled study

Brink-Elfegoun et al. Journal of the International Society of Sports Nutrition 2014, 11:46 http://www.jissn.com/content/11/1/46 RESEARCH ARTICLE Open Access Effects of sports drinks on the maintenance of physical performance during 3 tennis matches: a randomized controlled study Thibault Brink-Elfegoun1, Sébastien Ratel2,10, Pierre-Marie Leprêtre3, Lore Metz2,10, Gael Ennequin2,10, Eric Doré2,10, Vincent Martin2,10, David Bishop4,5, Nicolas Aubineau6, Jean-François Lescuyer6, Martine Duclos7,8,9,10, Pascal Sirvent2,10* and Sébastien L Peltier6 Abstract Background: Tennis tournaments often involve playing several consecutive matches interspersed with short periods of recovery. Objective: The objective of this study was firstly to assess the impact of several successive tennis matches on the physical performance of competitive players and secondly to evaluate the potential of sports drinks to minimize the fatigue induced by repeated matches. Methods: This was a crossover, randomized controlled study. Eight male regionally-ranked tennis players participated in this study. Players underwent a series of physical tests to assess their strength, speed, power and endurance following the completion of three tennis matches each of two hours duration played over three consecutive half-days (1.5 day period for each condition). In the first condition the players consumed a sports drink before, during and after each match; in the second, they drank an identical volume of placebo water. The results obtained were compared with the third ‘rest’ condition in which the subjects did not play any tennis. Main outcomes measured were maximal isometric strength and fatigability of knee and elbow extensors, 20-m sprint speed, jumping height, specific repeated sprint ability test and hand grip strength. Results: The physical test results for the lower limbs showed no significant differences between the three conditions. Conversely, on the upper limbs the EMG data showed greater fatigue of the triceps brachii in the placebo condition compared to the rest condition, while the ingestion of sports drinks attenuated this fatigue. Conclusions: This study has demonstrated for the first time that, when tennis players are adequately hydrated and ingest balanced meals between matches, then no large drop in physical performance is observed even during consecutive competitive matches. Trial registration: ClinicalTrials.gov: NCT01353872. Keywords: Tennis, Nutrition, Fatigue, Performance, Sports drinks * Correspondence: 2 Clermont Université, Université Blaise Pascal, EA 3533, Laboratoire des Adaptations Métaboliques à l’Exercice en conditions Physiologiques et Pathologiques (AME2P), Bâtiment Biologie B, 24 avenue des Landais, BP 80026F-63171 Aubière Cedex, France 10 CRNH-Auvergne, Clermont-Ferrand F-63001, France Full list of author information is available at the end of the article © 2014 Brink-Elfegoun et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Brink-Elfegoun et al. Journal of the International Society of Sports Nutrition 2014, 11:46 http://www.jissn.com/content/11/1/46 Introduction Tennis tournaments are quite complex due to their variability in terms of exercise duration and the type of effort required. One feature of competitive tennis is that the season is relatively long and that the ranking system pushes players to compete all year long. During a competition, players must sometimes play one or two matches a day on consecutive days. For many reasons the duration and intensity of these matches are highly variable, but it is not uncommon to see matches continue beyond three hours [1,2] and various studies have shown a drop in high-level tennis performance during extended matches [3-6]. Under these conditions, optimum recovery methods are needed to maintain a high level of performance over the duration of a match, tournament or season. Among the strategies used, nutrition appears to be an important element to consider [7]. The majority of studies on the impact of nutritional strategies on tennis performance have been conducted by taking measurements during or at the end of long matches. Some studies have suggested a beneficial effect of carbohydrates during prolonged tennis matches [4,5,8-10]. Caffeine has also been suggested as positively affecting performance, although the number of relevant studies is very limited [4,5,9]. Among less common nutritional strategies, one study has also demonstrated a beneficial effect of sodium bicarbonate [6]. On the other hand, creatine supplementation did not appear to lead to positive effects on tennis performance [11,12]. To our knowledge, no study has evaluated the effects of nutritional strategies on physical performance in the days following a series of matches, despite this being the reality of competitive tennis. Furthermore, studies conducted in the field of tennis nutrition have only been interested in the isolated effects of nutritional strategies before or during the match. However, it is increasingly common for competitive athletes to use sports drinks before, during and after matches to help maintain their performance over the duration of a tournament [13]. Different types of commercial beverages, specifically formulated to meet the needs of athletes before, during or after exercise, have been developed and introduced into the market in recent years, even though the claimed benefits of these advertised products have usually not been scientifically proven [14]. Recently, we have conducted a controlled, randomized, double-blind study to evaluate the impact of ingesting specially formulated pre-exercise, endurance, and recovery sports drinks on glycaemia and tennis performance indices during a simulated tennis tournament [15]. We observed that this nutritional strategy allowed higher stroke frequency during play, with decreased rates of perceived exertion. In this follow-up study we investigated the effects of this nutritional strategy on physical Page 2 of 10 performance. Physical performance was assessed by a series of physical tests which determined strength, speed, power and endurance of the subjects following the end of the tennis tournament simulation in each condition (placebos and sports drinks). Our hypotheses were that physical performance would naturally decrease over the matches and that the sports drinks would limit this fatigue. Methods Trial design This was a single-center, double-blind, placebo-controlled, cross-over trial conducted in France. It was performed according to Good Clinic (...truncated)