Dragon ball Raging Blast - Power up help

Ok im getting this game for x mas after i enjoyed the demo. Ok one thing that annoys me so much is there is a way to charge up your character. You like let energy fly around you and your power bar fills, what buttons do i have to press to do this because its not on the skill list and it seems its just common knowlage that i dont know. Can someone please tell me how to do it. Its like somthing you do and you stand still but power up your character and then gives you more powers to do as you are fully charged
please helpim going insane, Joey :)