Knees are best delivered while grabbing the opponent and pulling the target area towards the striking instrument, however, they can be delivered without grabbing. Jumping into the air while delivering a knee strike can add power to the technique. Standing on tip-toes or the ball of one's foot while delivering a knee strike with the other leg is unique to this art.
It is believed that doing so adds power to the technique and increases the reach of the attacking leg. Both knees can strike straight upwards simultaneously towards the chest, head, shoulders, or solar plexus of the opponent and such a technique is called the double knee.