In-season effect of a combined repeated sprint and explosive strength training program on elite junior tennis players.

The aim of this study was to analyze the effects of a combined explosive strength (ExpS) and repeated sprint (RS)-training program (2 times per week) on performance (sprint, jumping ability, and RS ability [RSA]) in young elite tennis players during a competitive period. Eight competitive internationally ranked male junior tennis players participated in an 8-week training intervention. After training, except for percentage of decrement in the RS test (p = 0.72) and maximal aerobic performance (p = 1.0), all performance variables (i.e., sprint, countermovement jump, and RSA) were significantly improved (p ≤ 0.05; effect sizes ranging from 0.56 to 1.12). Although one can expect greater effects of ExpS or RS training programs alone than a combined program, the results obtained here show that the inclusion of a combined ExpS and RS training program seems to be an effective training tool to improve neuromuscular performance (i.e., changes in jumping ability and single sprint) as well as RSA in high-level tennis players.

Recovery interventions and strategies for improved tennis performance.

Improving the recovery capabilities of the tennis athlete is receiving more emphasis in the research communities, and also by practitioners (coaches, physical trainers, tennis performance specialists, physical therapists, etc). The purpose of this article was to review areas of recovery to limit the severity of fatigue and/or speed recovery from fatigue. This review will cover four broad recovery techniques commonly used in tennis with the belief that the interventions may improve athlete recovery and therefore improve adaptation and future performance. The four areas covered are: (1) temperature-based interventions, (2) compressive clothing, (3) electronic interventions and (4) nutritional interventions.

Tennis physiology: training the competitive athlete.

The game of tennis has evolved from the wooden-racket era of long, crafty points based on style and finesse, to the current fast paced, explosive sport based on power, strength and speed, where 210 km/h serves are common. This evolution over the last 20 years has led to an increased interest in tennis research. Competitive tennis athletes need a mixture of anaerobic skills, such as speed, agility and power, combined with high aerobic capabilities. The work-to-rest ratios of competitive tennis athletes range between 1 : 3 and 1 : 5, and fatigue has been shown to greatly reduce the hitting accuracy. Competitive male tennis athletes maintain body fat <12% and have maximal oxygen uptake values >50 mL/kg/min, and as high as 70 mL/kg/min. Results from lactate testing in tennis players are inconclusive as some studies have shown increased levels, whilst other studies have shown little or no change. Further investigation is required to determine the production and utilisation effects of lactate from playing tennis. The average length of time to play a point in tennis is <10 seconds and this has declined substantially in the last 20 years. Further research is needed to investigate tournament performance and its effect on fatigue, recovery, hormonal and injury levels. As the game of tennis continues to change, the physiological parameters must be continually investigated to help provide athletes, coaches and trainers with information that will aid in the development of efficient and productive tennis performance and injury prevention programmes.

Physical performance changes after unsupervised training during the autumn/spring semester break in competitive tennis players.

BACKGROUND: All competitive tennis players take time away from coaches throughout the year; however, little information is available as to the short-term physiological effect of these breaks. OBJECTIVE: The purpose of this investigation was to evaluate the impact of a 5 week off-campus structured, yet unsupervised, break from regular training in top collegiate tennis players. METHODS: A nationally ranked collegiate NCAA Division I male tennis team (n = 8) performed a test battery in December and again in January after a 5 week period of recommended, yet unsupervised, training. The tests performed were 5, 10 and 20 m sprints, spider agility test, medicine ball power throws, standing long jump, Wingate anaerobic power test, VO2max, push-up and sit-up test, grip strength and range of motion (ROM) measures (goniometer) of the shoulder, hip, hamstring and quadriceps. RESULTS: Paired t tests (p<0.05) showed significant decreases in mean (SEM) Wingate power measurements in Watts/kg (pre: 8.35 (0.19) w/kg ; post: 7.80 (0.24) w/kg ), minimum Wingate power (pre: 5.89 (0.27) w/kg; post: 5.10 (0.38) w/kg) and VO2max values (pre: 53.90 (1.11) ml/kg/min; post: 47.86 (1.54) ml/kg/min). A significant increase was seen in the athlete's fatigue index (pre: 44.26 (2.85)%; post: 51.41 (3.53)%), fastest 5 m (pre: 1.07 (0.03) s; post: 1.12 (0.02) s), 10 m (pre: 1.79 (0.03) s; post: 1.84 (0.04) s) and 20 m (pre: 3.07 (0.05) s; post: 3.13 (0.05) s) sprint times. No significant differences were seen for the other variables tested. CONCLUSIONS: These results suggest that a 5 week interruption of normal training can result in significant reductions in speed, power and aerobic capacity in competitive tennis players, likely owing to poor compliance with the prescribed training regimen. Therefore, coaches and trainers might benefit from techniques (eg, pre- and post-testing) requiring athletes' to have accountability for unsupervised workouts.

Use of nutritional supplements and ergogenic aids in professional tennis players.

INTRODUCTION: Nutritional supplements and ergogenic aids (NS&EA) are used between training/matches with the goal of enhancing tennis performance. Scientific literature about prevalence and use of NS&EA in professional tennis players is scarce. OBJECTIVE: The aim of the study was to describe the NS&EA used by professional tennis players during a season. METHODS: Using a validated self-administered questionnaire, 62 professional male and 9 professional female tennis players (11% in their gender specific top 100 tennis world ranking (i.e.,ATP/WTA)) registered all the used NS&EA. RESULTS: Eighty-one percent of the participants declared taking at least one NS&EA. Strength and conditioning trainers (S&C) and tennis coaches were the professionals who recommended most of the NS&EA in the players outside the TOP-100 (OT100; 50.7% and 39.1%, respectively). However, sports nutritionist were the principal advisors in the top-100 tennis players (T100; 62.5%). Sports drinks were the NS&EA most commonly used by all participants (81.7%). T100 participants used caffeine (p = 0.042), creatine (p = 0.001), iron (p = 0.013) and CHO-protein mix (p = 0.033) significantly more frequently that OT100 players. CONCLUSIONS: There is a high prevalence of NS&EA use among professional tennis players independently of their tennis ranking position. However, T100 tennis player have an increased use of certain substances such us caffeine, creatine, iron and CHO-Protein mix. For the rest of the studied NS&EA the use was similar between T100 and OT100 players. It is possible that the differences in NS&EA use between groups could be related to the different professionals on charge of nutritional advice in T100 vs OT100.

Hydration and temperature in tennis - a practical review.

Competitive tennis is typically played in warm and hot environments. Because hypohydration will impair tennis performance and increases the risk of heat injury, consumption of appropriate fluid levels is necessary to prevent dehydration and enhance performance. The majority of research in this area has focused on continuous aerobic activity - unlike tennis, which has average points lasting less than ten seconds with rest periods dispersed between each work period. For this reason, hydration and temperature regulation methods need to be specific to the activity. Tennis players can sweat more than 2.5 L·h(-1) and replace fluids at a slower rate during matches than in practice. Latter stages of matches and tournaments are when tennis players are more susceptible to temperature and hydration related problems. Sodium (Na(+)) depletion, not potassium (K(+)), is a key electrolyte in tennis related muscle cramps. However, psychological and competitive factors also contribute. CHO drinks have been shown to promote fluid absorption to a greater degree than water alone, but no performance benefits have been shown in tennis players in short matches. It is advisable to consume a CHO beverage if practice or matches are scheduled longer than 90-120 minutes. Key PointsAlthough substantial research has been performed on temperature and hydration concerns in aerobic activities, there is little information with regard to tennis performance and safetyTennis athletes should be on an individualized hydration schedule, consuming greater than 200ml of fluid every changeover (approximately 15 minutes).Optimum hydration and temperature regulation will reduce the chance of tennis related muscle cramps and performance decrements.

An epidemiological study of interdigital cysts in a research Beagle colony.

Interdigital cysts are chronic inflammatory lesions that can be found in dogs. In order to better understand their etiology, we completed a retrospective analysis of epidemiologic factors by using the clinical records from 743 research Beagles at our research site. Factors examined included age, gender, weight, body condition score, location of the cyst, and type of cage flooring. Statistical analysis revealed that age, body condition score, and type of flooring were all significant factors in the occurrence of interdigital cysts. The epidemiological evidence supports the hypothesis that interdigital dermatitis is the inciting cause of interdigital cysts.

A review of fluid and hydration in competitive tennis.

Hypohydration is known to impair performance and increases the risk of heat injury. Therefore, the consumption of appropriate fluid volumes before, during, and after tennis play is important to maintain physiological homeostasis and performance. Tennis is a sport that typically has points lasting fewer than ten seconds, with short-to-moderate rest periods between each work bout. This sequence is repeated over hours. Most fluid and hydration research has focused on continuous aerobic exercise, which provides vastly different physiological strain compared with tennis practice and competition. Consequently, practical recommendations on maintaining hydration status for aerobic continuous exercise may not be appropriate for tennis athletes. Tennis players can sweat more than 2.5 L.h(-1) and replace fluids at a slower rate during competition than in practice. In warm and hot environments, electrolyte-enhanced fluid should be consumed at greater than >200 mL per changeover and ideally closer to 400 mL per changeover. Tennis scientists, coaches, and players need to individualize hydration protocols to arrive at the optimal hydration strategy.

Comparison of the stress response in rats to repeated isoflurane or CO2:O2 anesthesia used for restraint during serial blood collection via the jugular vein.

The primary objective of this study was to compare the effect of 2 commonly used anesthetics, isoflurane and CO2, on the physiologic stress hormone, corticosterone, in rats during serial blood collections. Circulating corticosterone concentrations were monitored during serial jugular blood sampling in rats exposed to either isoflurane or CO2 anesthesia. Blood was drawn under anesthesia at 6 time points (initial sampling and 0.5, 1, 2, 3, and 24 h after initial sampling) across a 24-h period. The results indicated that corticosterone levels in both anesthesia groups showed a similar pattern of stimulation, indicated by a sharp increase in circulating concentrations by the 0.5-h time point, with further elevation at 1 h, and a decline at subsequent time points. Isoflurane-treated animals showed higher baseline levels of corticosterone at the initial sampling. However, the increase in corticosterone at subsequent time points was significantly higher for animals exposed to CO2, suggesting that the cumulative effects of repeated exposure to stressful stimuli was more evident for this type of anesthesia. The apparent reduction in stress effects of isoflurane as opposed to CO2, coupled with other published adverse effects of CO2, suggests that isoflurane is the better choice when anesthesia is needed for serial blood collection. However, availability of equipment for delivery of anesthetic, scavenging of waste gasses, familiarity of personnel with the anesthetic, and the potential effect of the anesthetic on research endpoints should all be considered in choosing between the 2 anesthetics.