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

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

The effects of a calf pump device on second half performance of a simulated soccer match in competitive youth players

During soccer matches, performance decrements have been reported that relate to both physical abilities and technical skills. To investigate the effects of low-frequency electrical stimulation LFES (VeinoplusSport®, Ad Rem Technology, France) administered during half-time recovery on performance alterations during the second half. Twenty-two highly trained young players undertook a soccer-match simulation (SAFT90). During half-time, they were randomly assigned to LFES group or Placebo group. Each half was split into 3 bouts of 12 minutes. Following each bout, maximal strike speed (MSS), sprint test (ST), maximal sprint accelerations (MA) and metabolic power (MP) were determined in both groups. Arterial (AF) and venous flows (VF) were measured at rest and at the end of half-time. LEFS group exhibited beneficial effects on performance compared to the Placebo group with a likely effect for MSS, ST, MA, and a possible effect for MP. AF and VF increased statistically more in LEFS group compared to Placebo group. The use of specific calf-pump LFES during half-time of a youth simulated soccer match attenuated the decrease in performance during the second half compared to Placebo group. This effect is most marked at the beginning of the second half with regards to explosive parameters

The effects of a calf pump device on second half performance of a simulated soccer match in competitive youth players

International audienc

Diet- but not exercise-induced iso-energetic deficit induces compensatory appetitive responses

International audienc

Adaptations de la fonction mitochondriale dans le muscle squelettique de rat : comparaison entre un programme d’entrainement en concentrique et deux programmes d’entrainement en excentrique.

National audienceLe but de cette étude est de comparer les adaptations de la fonction mitochondriale en réponse à un entrainement concentrique ou excentrique. Deux types d’exercices excentriques ont été réalisés. Le premier (EXC -30) a été exécuté à même puissance métabolique que l’exercice concentrique (CONC +15). Le deuxième (EXC -15) a été exécuté à même puissance mécanique que l’exercice concentrique. Un groupe contrôle (CONT) sans entraînement a également été étudié. Nous émettons les hypothèses suivantes : 1/ Les deux types d’exercices excentriques permettront une amélioration de la fonction mitochondriale par rapport à CONT. 2/ L’exercice excentrique réalisé à même puissance métabolique permettra des adaptations dans des proportions similaires à celles induites par l’exercice concentrique. Après 26 jours d’entrainement, des mesures d'oxymétrie réalisées sur fibres perméabilisées dans le gastrocnémien (GAS) et le vaste interne (VI) ont montré que la constante d'affinité de la mitochondrie pour l'ADP (Km) a significativement augmenté dans le groupe EXC -30 et CONC +15 en comparaison au groupe CONT. Aucune différence significative n’a été mise en évidence concernant la vitesse maximale de respiration entre les différents groupes. La quantification de l’expression des gènes par RT-PCR dans le GAS a montré une augmentation de PPAR-β dans le groupe EXC -15 comparé au groupe CONT. Dans le VI, seule une augmentation significative de PGC-1α a été notée dans le groupe EXC-30 comparé au groupe CONT. L'activité de la citrate synthase n'a montré aucune différence significative entre les groupes. Au niveau protéique, les résultats des Western-blots ont révélé une augmentation significative de la porine du groupe EXC-15 comparé aux trois autres groupes, mais uniquement dans le VI. Les complexes de la chaine respiratoire et la desmine ne présentaient aucune différence significative d’expression quel que soit le muscle étudié. Un entrainement en excentrique de 26 jours conduit à différentes adaptations au niveau de la fonction mitochondriale, avec notamment une augmentation du Km dans des proportions similaires à un entrainement en concentrique. D’autres investigations sont nécessaires afin d’élucider les mécanismes cellulaires permettant l’amélioration de la fonction mitochondriale suite à un exercice excentrique

Diet- but not exercise-induced iso-energetic deficit induces compensatory appetitive responses

Although physical exercise and dietary restriction can be both used to induce energy deficits, they have been suggested to favor different compensatory appetitive responses. While dietary restriction might favor increased subsequent energy intake and appetite sensations, such compensatory responses have not been observed after a similar deficit by exercise. The present work provides a first overview of the actual evidences discussing the effects of iso-energetic deficits induced by exercise versus dietary restriction on subsequent energy intake, appetite sensations, and on the potentially involved hedonic and physiological mechanisms

Effects of pre-exercise, endurance, and recovery designer sports drinks on performance during tennis tournament simulation

Sports drinks are often used before, during, and after tennis tournaments, but their ability to influence physiological and psychological variables and the characteristics of tennis match play remains uncertain. The objective of this study was to evaluate the impact of ingesting specially formulated pre-exercise, endurance, and recovery sports drinks on glycemia and performance indices during a simulated tennis tournament. Eight well-trained male tennis players performed two 3-match round-robin tennis tournaments although ingesting sports drinks (SPDs) or placebos (PLAs) before, during, and after each match (crossover study design). Before the first tournament, match and drink order were randomized (SPDs or PLAs first) and players were placed under controlled nutritional and hydration conditions. Glycemia, heart rate response, rate of perceived exertion, and notational/match analysis were assessed during each match. Sports drinks maintained higher glycemia levels during match 2 and 3 of the tennis tournament compared with PLAs (p , 0.01). Moreover, higher mean heart rates (p , 0.01) and stroke frequencies (p , 0.01) concomitantly with lower rates of perceived exertion (p , 0.01) were recorded throughout the duration of the tournament, when players used the SPDs. During a 3-match tennis tournament, SPDs allow higher stroke frequency during play, with decreased rates of perceived exertion.© 2013 National Strength and Conditioning Association

Improved walking energy efficiency might persist in presence of simulated full weight regain after multidisciplinary weight loss in adolescents with obesity: the POWELL study

International audienc