f(x) returns to Music Core this week with yet another electrifying performance of NU ABO! The girls are hitting up the stage once again with another unforgettable performance of their latest hit! Although it has been awhile since the girls have been promoting NU ABO, the song never wears off, don't you think? With the addictive beat and catchy dance, these girls have certainly gotten the attention of everyone! http://www.youtube.com/watch?v=5-GNTIW2Ha0 There was some alarm among fans after it was noted that Amber had done the performance while sitting in a chair. It was revealed by SM Entertainment afterwards that Amber had suffered an ankle injury but it was not serious. The chair arrangement was just a safety precaution to protect her injured ankle.