Mediterranean type nutritional diet applied to elite tennis players; effects on body components, strength, endurance and tennis performance

"The Effects of Mediterranean-Type Diet Applied to Elite Tennis Players on Body Composition, Strength, Endurance, and Tennis Performance" In this study, the aim was to investigate the changes in body composition, strength, endurance, and tennis performance expected in adolescent elite tennis players during an 8-week period while implementing a Mediterranean-type diet. The research was conducted between October 2022 and December 2022 at private tennis clubs in Afyonkarahisar and Uşak city centers with the voluntary participation of 30 male and female tennis players aged between 12 and 15 years, who had been regularly participating in national and international tournaments for at least 3 years. The tennis players were divided into two groups: the experimental group, consisting of tennis players from Afyon city center, and the control group, consisting of tennis players from Uşak city center, with an equal number in each group (n=15). During the 8-week study, the control group followed only standard tennis training, while the experimental group followed the Mediterranean-type diet in addition to standard tennis training, which was individually organized. The adherence and continuity of the diet for the experimental group and their families were monitored through online video meetings and face-to-face individual consultations. Both groups showed consistent attendance to their training sessions, which were conducted 3 to 4 days per week, 2 hours each.Prior to the tests, the athletes underwent a 15-minute general warm-up protocol. To assess the athletes' adherence to the Mediterranean diet, the "Mediterranean Diet Quality Index (KIDMED)" was applied before the research. Three consecutive days of food consumption records and dietary frequency were collected from both groups, with one of the days being a weekend day. During data collection, any missing or incorrect parts were addressed by consulting with the individuals, and necessary corrections were made.The study employed various tests to measure the athletes' performance. The 12-minute running test was used to assess endurance performance, static vertical jump and standing long jump tests were utilized to measure strength performance, and the International Tennis Numbering test measurements were used to evaluate tennis performance level. To determine the athletes' body composition, biometric impedance analysis was used, and height and waist circumference measurements were taken. Body mass index (BMI) values were calculated using the collected data. Measurements were conducted twice, both before and after the 8-week intervention.The data were analyzed using the SPSS program, and the Shapiro-Wilk test was used to assess the normality of the data. The data were found to have a normal distribution, as the Skewness and Kurtosis values were within the accepted range of -3 to +3. Descriptive statistics, including frequency (f), percentage (%), mean, and standard deviation, were used in the analysis. Additionally, a dependent sample t-test was employed for within-group pre-test and post-test comparisons, and an independent sample t-test was used for comparing the differences between groups' pre-test and post-test results. The 2*2 ANOVA test was utilized to detect group-time interactions.The results showed statistically significant differences between the experimental group's pre-test and post-test measurements in height, body weight, BMI, waist circumference, vertical jump, endurance performance, and tennis performance scores (p<0.05). Similarly, the control group exhibited statistically significant differences between pre-test and post-test measurements in height and endurance performance test results (p<0.001, p<0.05). There were also statistically significant differences between the experimental and control groups' post-test measurements in vertical jump (p<0.005), tennis performance in terms of serving (p<0.028), and total score (p=0.05) (p<0.05). The ANOVA test results to determine group-time interactions revealed significant differences in body weight, BMI, waist circumference, vertical jump, ITN accuracy, service, and total score parameters.In conclusion, it is believed that the Mediterranean-type diet applied to adolescent elite tennis players can positively contribute to vertical jump (strength) and tennis performance. The results suggest that this dietary intervention may have beneficial effects on the athletes' performance in these areas. Keywords: Mediterranean Diet, Endurance, ITN Score, KIDMED, Tennis, Strength