[1] She represented South Korea, as a 15-year-old, at the 2000 Summer Olympics, and later helped her squad capture the bronze medal for the host nation at the 2002 Asian Games.

[2] In the 200 m breaststroke, Ku failed to advance to the top 8 final, as she finished her semifinal run with an eleventh-place time in 2:28.50.

[3][4] Earlier in the prelims, she made a surprise packet with a new South Korean record of 2:28.21 from an outside lane in heat four to pick up a similar seed for the top 16 field.

Swimming the breaststroke leg in heat two, Ku recorded a split of 1:10.89, but the South Koreans rounded out a six-team field to last place and seventeenth overall in a final time of 4:16.93.

[7][8] When her nation hosted the 2002 Asian Games in Busan, Ku gave the South Korean home crowd a further reason to celebrate, as she shared bronze medals with Shim Min-ji and newcomers Park Kyung-hwa and Sun So-eun in the 4×100 m medley relay (4:13.41).