Why didn't IU participate in the "Idol Star Athletics & Swimming Championships" matches?

Viewers of MBC's Lunar New Year special, "Idol Star Athletics & Swimming Championships," noticed that singer IU was not present during the program's matches, and began wondering where she had disappeared to after taking the athlete's oath. A representative of MBC spoke through Newsen on February 7th and revealed, "IU took the oath alongside Nichkhun and Kim Dong Wan, but she was not able to participate in the matches." IU was put on the same team as Big Bang's Seungri, but due to the heavy snowfall that day, recordings were delayed, forcing IU to leave the set hurriedly for her�"Dream High" schedule. The representative continued, "If she did not take the oath as a representative of the athletes, she would not have participated in the matches at all.�Her drama schedule is quite rigorous, so there were talks of her just briefly stopping by before leaving beforehand." 2PM's Taecyeon, Wooyoung, miss A's Suzy, and T-ara's Eunjung were also absent from the program due to "Dream High" as well. Source: Newsen via Joins