Effect of high intensity interval training on cardiopulmonary function in Taekwon-do ITF athletes

International Taekwondo Federation-sanctioned competition involves two rounds of 2 min sparring interspersed with a 1 min rest period. The organizational structure of taekwondo (TKD) results in a physical activity characterized by concomitant lowand high-intensity efforts that require specific training adaptations for athletic performance [1]. Research on the physiological demands of competitive TKD has found it in volv es significant anaerobic energy expenditure supported throughout by the aerobic pathway [2,3,4]. Matsushige et al. [5] further articulated this interaction finding that muscle anae robic metabolism is critical during the striking phases whereas the aerobic system is dominant during active recovery while also a significant contributor to the body’s ability to regenerate energy. It can be therefore assumed that a block, kick, or punch delivered with high power–speed mobilizes ana erobic ATP resynthesis and that only during the low-intensity recovery periods characterized by defensive movements be tween attacks is aerobic metabolism and the removal of ex cess lactate (LA-) stimulated. The fighting dynamics of TKD as well as the adopted mo vement patterns (especially in lower weight classes) often elicit maximum heart rate and very high blood lactate levels (11-14 mmol/l plasma) [3,4]. The intensive nature of TKD therefore requires athletes with highly developed glycolytic capacity so as to present sufficient defense mechanisms against respiratory acidosis and, consequently, reduced performance. For this reason, the physiological and metabolic adaptations induced by interval training seem ideally suited for TKD and other com bat sport athletes. Research on this training modality, such as by Burgomaster et al. [6], found that interval training increases pyruvate oxidation via enhanced pyruvate de hy drogenase and citrate synthase activity, both of which are important en zymes in the aerobic energy system. These results are consistent with those presented in other studies [7,8], who in ad dition to changes in the enzymatic activity of the glycolytic and aerobic energy systems also observed improved aerobic and anaerobic performance. Another confirmation of the positive effects of glycolytic-based interval training on aerobic capacity is through significant improvements in endurance efforts at