Ok so say your goku and your super saiyan. What you can do is you start charging energy to replenish ki. Once your full you would keep charging, and then use an attack (kamahamaha for example). Your powerlevel would become higher as you charge the attack because you put yourself to the limits charging the wave, after the wave hits the max a yellow bar would begin to cover green bar, and the bar itself would be longer, and there would be another bar at the near end of the bar. Your body would begin to have electricity pulse around you, and your attack would glow much more brighter. Your pl still rises, but if the yellow color goes to the second bar at the end of the charge, your power would go insane and go to far for the bounds of your form, and the beam would explode in your hand, destroying you and alot around you. If of course you didnt blow yourself up and you fire the beam, much stronger than normal, at an opponent, and on your radar it can show up as a large dot blinking and heading at you, showing you its a high powered energy attack. Your enemy would turn to see it O_O and of course, would probably get hit. Your energy will have drained, and you fall to earth, stunned for a moment, and then you may replenish your ki and continue fighting. (This idea i thought of when i saw the cell saga, vegeta yelled at cell "Want to test you power? Then stand right there!" when he was overpowering his final flash)