At many American sporting events, if a player with a "u" sound in his name is on the home team, and he enters the game or makes a play in the game, then there is a good chance the fans will chant his name with an extended "u" sound.
Here are a few examples:
Whenever fullback John Kuhn of the Green Bay Packers touches the ball at a home game, then the fans will chant "Kuuuuuuuuuhn".
In the 1990s, Daryl Johnston was a fullback with the Dallas Cowboys. His nickname was "Moose". Whenever he touched the ball at a home game, the fans would chant "Moooooooose".
Luke Walton was a basketball player for the L.A. Lakers, and whenever he entered a game at home, the fans would chant "Luuuuuuuuke".
In the 1980s, Joe Dumars was a basketball player for the Detroit Pistons, and whenever he scored a basket at a home game, the P.A. announcer would yell "Joe Duuuuuuuuumars!"
When did this tradition originate?