Ollie

The ollie was a skateboarding trick where the participant leapt into the air without using his or her hands. To do so, according to Alan Jackson, one had to bend their knees. When Clyde Langer failed to do so, and so only managed to fall to the ground, Alan, having been named King of the Concrete in his youth, demonstrated the proper way of doing it. (TV: Whatever Happened to Sarah Jane?)