The effect of acute consumption of red beet juice on aerobic and anaerobic power of amateur karate girls

Red beet juice is a rich source of nitrate. Nitric oxide has the ability to stimulate vasodilation; Which increases blood flow to the muscle. Due to the involvement of aerobic and anaerobic systems in karate, the aim of this study was to investigate the effect of red beet juice on aerobic and anaerobic power of karate girls.

For this purpose, 10 club-level female karate players in the black belt category, two and three, were voluntarily studied in a cross-sectional, randomized, double-blind study. Subjects arrived at the gym at 7:30 a.m. and rested for 90 minutes after consuming red beetroot juice (100 ml) or placebo (blueberry juice) and taking the test at 9:00 a.m. First, 10 minutes of dynamic warm-up including walking and stretching movements were performed, then 4×9 test, RAST test and finally karate aerobic test was performed. In this aerobic test, the subjects guarded the punching bag consecutively. They were moving like a real combat during the recovery. The test ended when the subject was no longer able to continue the blows. In this case, the time was kept constant and the obtained number was recorded as fatigue time and test stage. Three minutes of active rest were determined between each test. After one week, the groups of subjects were transferred and the mentioned tests were performed again. Statistical analysis was reported using paired t-test and SPSS software version 26.

The results showed that with consumption of red beet juice compared to placebo maximum power (P = 0.014), minimum power (P = 0.025), average power (P = 0.011), fatigue index (P = 0.022) and Speed drop index (P = 0.020) improved significantly in RAST test. There was also a significant decrease in agility test time (P = 0.039). But there was no significant difference in karate specific aerobic test (P = 0.099) and perceived exertion (P = 0.685).

According to the results of the present study, consumption of red beet juice is effective in anaerobic performance and agility of karateka. But the amount of change in aerobic performance in the special karate test was not significant. Therefore, according to the results, it seems that consuming red beet juice can be useful for these athletes.