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.
维普
万方数据
