Acute doses of beetroot juice supplementation on aerobic and anaerobic performance of trained male taekwondo athletes v1

Studies have shown that Nitrate (NO3-) rich beetroot juice (BJ) supplementation improves endurance and high-intensity intermittent exercise. The dose-response effect on taekwondo of BJ supplementation are yet to be determined. This study aimed to investigate two acute doses of 400 mg of NO3-(BJ-400) and (800 mg NO3- (BJ-800) on taekwondo-specific performance tests compared with a placebo (PL) and control (CON) conditions. Eight trained male taekwondo athletes (age: 20±4 years, height: 180±2 cm, weight: 64.8±4.0 kg) completed four experimental trials using a randomized, double‐blind placebo‐controlled design: BJ-400, BJ-800, PL, and CON. Countermovement jump (CMJ) was performed before the Multiple Frequency Speed of Kick Test (FSKT) and Progressive Specific Taekwondo Test (PSTT), respectively, whereas cognitive function was assessed (via the Stroop test) before and after supplementation and 10 minutes following PSTT. Blood lactate was collected before the CMJ tests, immediately, and 3 minutes after the FSKT and PSST, with rating of perceived exertion (RPE) was recorded during and after specific taekwondo tests. Nosignificant difference between conditions were observed (p> 0.05)for PSTT and FSKT performances. In addition, blood lactate, RPE, heart rate, and CMJ height and performance during the specific taekwondo tests were not significantly different among conditions (p> 0.05). However, after the PSTT test, cognitive function was higher in BJ-400 compared to other treatments (p< 0.05). In conclusion, acute intake of 400 and 800 mg of NO3-rich BJ did not improve taekwondo-specific performance tests in trained male taekwondo athletes.