Abstract：The purpose of this study was to investigate the effects of 6-week bilateral (BI) or unilateral (UNI) kettlebell training on the balance ability and core stability in taekwondo athletes. Twenty-six taekwondo poomsae athletes were recruited into UNI (n = 13) or BI (n = 13) groups with a matched-pair of performing balance in hakdariseogi. All participants sustained the regular taekwondo poomsae training programs during the experimental period and had additional kettlebell training (4 movements for 3 sets) twice per week for 6 weeks. The radius and velocity of center of pressure (COP), the core stability test of isometric trunk extensor and flexor as well as abilities of right and left side plank were tested before and after the experiment. The results showed that the COP velocities for mediolateral displacement of dominant and non-dominant legs, as well as holding time of isometric trunk extensor and flexor exercise in both UNI and BI groups were significantly better after 6-week training than those of pre-training. The UNI group after training showed significant improvements in COP range for mediolateral and anterior-posterior displacements of both legs, as well as holding time of right side plank compared to pre-training. Moreover, COP range for mediolateral displacement of the non-dominant leg was significantly lower than pre-training in BI group. Nevertheless, there were no significant differences between the groups. We conclude that the UNI and BI kettlebell training twice per week for 6 weeks can improve the balance ability and core stability for taekwondo poomsae athletes. Moreover, there was no significant difference between UNI and BI kettlebell training. (Full text)