Effects Of Caffeine Combined With Carbohydrate Supplementation On Performance In Male Tennis Players

Objective:Since caffeine was removed from the doping ban list in 2004,its application in competitive sports has become increasingly popular,and a large number of related studies have emerged.Carbohydrates are one of the most commonly used supplements for tennis players in competitions.Therefore,on the basis of dietary support,this study intends to explore the use of sports nutrition supplements to improve the performance of high-level tennis players and delay fatigue,and to explore the combined use of caffeine and carbohydrates for the special physical quality of elite male tennis players and the impact of exercise performance during simulated competitions.Methods:The grip strength,T test,Repetitive-sprint ability（RSA）test and hit and turn tennis test（H&TTT）of 12 young men’s second-class tennis players were tested.Tennis special physical fitness tests,as well as tennis performance tests such as batting accuracy test,serve speed test,Stroop test and simulated competition.A placebo-controlled,double-blind,randomized crossover design was used.Each participant was tested four times under the conditions of taking placebo（PLA）,carbohydrate（CHO）,caffeine（CAF）or caffeine+carbohydrate（CAF+CHO）.Each test interval was one week.The results of quiet HR,BP and Stroop tests before and after taking CAF were analyzed by paired sample t test.In the special quality and ability test,the test results of grip strength,T test,RSA,H&TTT and HR during exercise were analyzed by one-way ANOVA.The data of 10 sprint times in RSA test were analyzed by repeated measurement two-way ANOVA.In the performance test,the accuracy score of hitting the ball,the speed of serving the ball,the data during the simulated competition（the success rate of serving the ball,the scoring rate of serving the ball,the success rate of receiving the ball,the scoring rate of receiving the ball,and the unforced error）,the correct rate and reaction time of the Stroop test and the data of HR,Bla,Glu and RPE during the exercise were analyzed by repeated measurement two-way ANOVA.Results:（1）The grip strength of habitual and non-habitual hands in CAF and CAF+CHO groups was significantly increased,and the T test time was significantly shortened（P<0.05）.The sprint time of RSA test in CAF group and CAF+CHO group was significantly shortened（P<0.05）,and the average sprint time of RSA test in CHO group was significantly shortened（P<0.05）.The number of sprints completed by H&TTT in CAF+CHO group was significantly increased（P<0.05）,and the total number of swings in CAF group and CAF+CHO group was significantly increased（P<0.05）.（2）CAF can significantly improve the accuracy of hitting and serve speed before the simulation game（P<0.05）.After the simulated competition,the batting accuracy test scores,the first and second maximum serve speeds of the CAF and CAF+CHO groups were significantly improved（P<0.05）.In the simulated competition,the first and second serve success rate and scoring rate,the receiving success rate and scoring rate of the CAF+CHO group were significantly improved（P<0.05）,and the unforced errors were reduced（P<0.05）.（3）After taking caffeine,systolic blood pressure increased,reaction time in Stroop test decreased and accuracy increased（P<0.05）.In the special quality test,HR_max,HR_mean,Glu and Bla in the CAF+CHO group were significantly increased（P<0.05）.In the Stroop test after simulated competition,the reaction time and accuracy of CAF and CAF+CHO groups were significantly improved under the conditions of consistency and inconsistency（P<0.05）.During the simulated competition,the CAF+CHO group could significantly improve HR_mean,HR_max,Glu and Bla levels（P<0.05）,CAF could significantly improve HR_maxand Bla levels（P<0.05）,and CHO group could significantly improve Glu and Bla levels（P<0.05）;RPE was significantly decreased in CAF and CAF+CHO groups（P<0.05）.Conclusion:The combination of caffeine and carbohydrates can improve the upper limb grip strength of tennis players,sensitive quality,aerobic endurance,as well as to maintain the intermittent sprint time and other physical ability,and in improving the aerobic capacity of tennis players and improve the RSA sprint time and shorten the decay rate in a more excellent performance.Caffeine intake 1 hour before the game can improve the accuracy of hitting,serve speed and cognitive ability.After the combination of carbohydrates during the game,it will prolong its excellent athletic performance compared with single intake,and will increase the success rate of serve,serve scoring rate and reduce unforced errors.The use of caffeine combined with carbohydrates can significantly improve the physical fitness of tennis players,and is conducive to more stable technical and tactical play and reduce batting errors in simulated competitions.