Effects of two different doses of carbohydrate ingestion on taekwondo-related performance during a simulated tournament

Background Carbohydrate (CHO) ingestion enhances exercise performance; however, the efficacy of CHO intake on repeated bouts of exercise simulating a taekwondo tournament is unknown. Therefore, the purpose was to compare the effects of two different doses of CHO on a sports-specific kicking test during a simulated taekwondo tournament compared to placebo (PLA). Methods In a double-blind, randomized-placebo controlled, cross-over trial, eleven junior male professional taekwondo athletes (age: 16 ± 0.8 years, body mass: 55.3 ± 7.3 kg) ingested one of three solutions: (i) high dose (C45): 45 g of CHO (60 g∙h − 1 ), (ii) low dose (C22.5): 22.5 g of CHO (30 g∙h − 1 ; both solutions containing 2:1 glucose:fructose), or a PLA immediately following each kicking test. The kicking test was repeated 5 times, separated by 45 mins of rest, simulating a typical taekwondo competition day. Ratings of perceived exertion (RPE) and gastrointestinal discomfort (GI) scores were collected immediately after, and blood glucose before each test. Results The results revealed that C45 and C22.5 did not improve total, successful, or percentage of successful kicks compared to PLA ( p > 0.05). Blood glucose was significantly higher following both CHO conditions compared with PLA across all five tests ( p < 0.05). There were no differences between treatments or across tests for RPE ( p > 0.05). Conclusion CHO intake, independent of the dose, did not alter taekwondo kick performance during a simulated taekwondo tournament.