Effects of Caffeine Combined with Carbohydrate Supplementation on Specific Physical Fitness in Male Tennis Players
Objective To explore the effect of caffeine combined with carbohydrate supplementation on the special physical quality of excellent tennis players.Methods The grip strength test,T test,repetitive-sprint ability(RSA)test,hit and turn tennis test(H&TTT)and other tennis special physical fitness tests were conducted on 12 young men's tennis secondary athletes.A placebo-controlled,double-blind,randomized crossover design was used.Each participant was tested four times under the condition of taking placebo(PLA),carbohydrate(CHO),caffeine(CAF)or caffeine+carbohydrate(CAF+CHO),with an interval of one week.Paired sample t test was used to analyze the resting heart rate(HR)and blood pressure(BP)before and after taking CAF.One-way analysis of variance was used to compare the results of tennis special physical fitness test after taking CAF+CHO and HR during exercise with PLA,CHO and CAF.Two-way repeated measures analysis of variance was used to compare the changes of Bla and Glu during exercise.Results(1)Systolic blood pressure increased significantly after CAF and CAF combined with CHO(P<0.05).(2)In the grip strength test,compared with PLA and CHO groups,the grip strength of habitual and non-habitual hands in CAF and CAF+CHO groups were significantly increased(P<0.01,P<0.05);in the T test,compared with PLA and CHO groups,the T test time of CAF and CAF+CHO groups was significantly shortened(P<0.05).In RSA test,compared with PLA,the average time of each sprint in CHO group and CAF+CHO group was significantly shortened(P<0.05),but CAF and CAF+CHO significantly reduced the attenuation rate of RSA test(P<0.01).In the H&TTT test,compared with PLA group and CHO group,the total number of swings in CAF group was significantly increased(P<0.01,P<0.05).Compared with the other three groups,the number of sprint finishes and the total number of swings in CAF+CHO group were significantly increased(P<0.01).(3)After taking CHO,CAF or CAF+CHO,the maximum heart rate and average heart rate in RSA test were significantly higher than those in PLA group(P<0.05),and the maximum heart rate and average heart rate in CAF and CAF+CHO groups were significantly higher than those in CHO group(P<0.01).In H&TTT test,compared with PLA group and CHO group,the maximum heart rate and average heart rate of CAF+CHO group were significantly increased(P<0.01),and the average heart rate of CAF+CHO group was significantly increased compared with CAF group(P<0.01),while the average heart rate of CAF group was only significantly increased compared with PLA group(P<0.05).(4)Before RSA test,the blood glucose value of CHO group and CAF+CHO group was significantly higher than that of PLA group(P<0.01,P<0.05),and there was no significant difference in blood lactic acid value among all groups.After RSA test,the blood glucose value of CHO group and CAF+CHO group was still significantly higher than that of PLA group(P<0.05,P<0.01).The blood lactic acid value of CAF+CHO group was significantly higher than that of PLA group(P<0.05).Before H&TTT test,the blood glucose of CHO group and CAF+CHO group was significantly higher than that of PLA group(P<0.05),and the blood glucose of CAF+CHO group was significantly higher than that of CAF group(P<0.05),and there was no significant difference in blood lactic acid values among all groups;after H&TTT test,there was no significant difference in blood glucose values among all groups.The blood lactic acid of CAF and CAF+CHO groups was significantly higher than that of PLA group(P<0.05,P<0.01),and the blood lactic acid of CAF+CHO group was significantly higher than that of CHO and CAF groups(P<0.05).Conclusion The tennis players who use caffeine(4mg/kg)improved the special performance of tennis players:increasing the grip strength of upper limbs,reducing the time of the T-test,shortening the decay rate of the RSA test,and increasing the number of completed grades of the H&TTT test.Combined with carbohydrate supplementation had a much better performance in terms of average time of the RSA,the number of completed grades of the H&TTT test,etc.Our results suggest that moderate doses of caffeine combined with sugar-sweetened beverages 1 hour before exercise were able to improve tennis-specific physical performance during exercise.
万方数据
维普
