Impacts Of Green Tea Extract On Aerobic Capacity Of Rowing Athletes

Purposes:The primary purpose of this study was to explore the effects of green tea extract on the antioxidant capacity and aerobic capacity of female rowing athletes by measuring changes in antioxidant enzymes and oxygen uptake after the athletes took green tea extract, the main components of which is tea polyphenols, and therefore, to provide guidance on selection nutritional supplements to improve athlete's performance in aerobic exercises.Methods:24 female rowing athletes in Wuhan Institute of Physical Education were randomly divided into case group and control group, each of which consisted of 12 subjects. A double blinded method was used to test the effects of green tea extract or placebo. In the first test (placebo control study), athletes in both case group and control group were given placebos one hour before they made every effort to row 2000 meters on power measuring instrument. Oxygen uptake, time used to row 2000 meters, concentrations or activities at 4 minutes after the instrumental exercise of blood lactate (BLA) level, serum urea, serum CK, serum SOD, GSH-PX, and CAT were measured. In the second test (green tea extract vs. placebo study), one hour before the instrumental exercise, athletes in case group were given green tea extract, while those in control group were given placebo. All indicators mentioned above were measured again with the same methods used in the first test.Results:Second test vs. first test in case group: our results showed that maximum to oxygen uptake (3622.6±69.7 ml/min in second test; 3592.8±68.1 ml/min in the first test), concentrations or activities at 4 minutes after the instrumental exercise of serum SOD (77.5±5.9 NU/L; 72.7±4.6 NU/L), GSH-PX (57.1±5.3 kU/L; 52.7±5.0 kU/L), and CAT (41.6±5.4 kU/L; 37.0±5.2 kU/L) increased significantly in the second test than in the first test in case group (matched pairs t-test, p<0.05). Time used to row 2000 meters was shorter in the second test than in the first test in case group, but the difference was not statistically significant (matched pairs t-test, p>0.05).Case group vs. control group in the second test: maximum to oxygen uptake (3622.6±69.7 ml/min in case group; 3566.3±88.1 ml/min in control group), concentrations or activities at 4 minutes after the instrumental exercise of serum SOD (77.5±5.9 NU/L; 72.7±4.2 NU/L), GSH-PX (57.1±5.3 kU/L; 53.0±5.1 kU/L), and CAT (41.6±5.4 kU/L; 37.0±5.6 kU/L) were much higher in case group than in control group (student's t-test, p<0.05). Time used to row 2000 meters was shorter in the case group than that in the control group, but the difference was not statistically significant (student's t-test, p>0.05).Conclusions:Taking green tea extract can significantly increase antioxidant capacity and therefore aerobic capacity.