Youngji used to be a CCM trainee and she was really good at dancing... She has danced to song like Sherlock(shinee) Bang(after school) Bad Girl Good Girl(Miss A) And many madami you will see proof in this links
paghahanap this for madami covers sa pamamagitan ng her : link
and also the boys cover : link
In the ipakita where they showed off charns and such she showed that she could dance to the songs (some of them)
In Weekly Idol there she danced to sherlock and warrior.
You could also paghahanap on google: Youngji dance.