By conventional measures, dart players are not the telegenic type. They mutter to themselves. They wear flamboyant polyester polos. They cradle their handful of tiny spears and stare at a fibrous board 7 feet, 9¼ inches away.

But professional darts has catapulted itself from musty British pubs onto millions of television sets across Europe, an insurgency by a working-class sport that has turned the best of its mostly middle-age players into stars.

The premier darting event, the William Hill World Championship, has grown into a three-week, $3 million purse affair, replete with cheerleaders and thunderous walk-on music. The most recent event was held from Dec. 13 to Jan. 1.

The sport’s promoters work tirelessly to ratchet up the show. One area of emphasis in recent years has been to encourage the players to show some emotion for the TV cameras, especially by celebrating after a big turn or win. Though mild by the standards of other professional sports, the yelps, fist pumps and prancing are setting up a clash with some traditionalists, to whom there is no greater sin than showing up your competitor.

The dispute is all part of a makeover of darts engineered by Barry Hearn, the silver-tongued chairman of the Professional Darts Corp., or PDC, and the mastermind behind the sport’s growth on TV.

Hearn said his message to players was unambiguous: “If you look bored, I’ve got no time for you.”

For years, professional dart associations have tried to shed the game’s links to the smoky pubs where it blossomed nearly a century ago. Beer has been banished from the stage. So have cigarettes. At the World Championship, which are held every January, players walk to their places through cheering throngs of fans.

Most of the players are OK with that (although some wear ear plugs to dampen the loud music). But the notion of midmatch celebrations has been contentious. In a sport as rhythmic as darts, even a moment of mugging for the crowd can throw off a competitor’s timing. As the match progresses and tensions mount, the situation can become strained.

A two-time world champion, Gary Anderson, was involved in an incident in December. His opponent, Gerwyn Price, came chest to chest with the mild-mannered Anderson as he shrieked in triumph over a particularly good turn. The sport’s regulatory body is now considering disciplinary action. And the PDC has begun reviewing whether it needs more referees and a system for docking points from players during a match.

The problem is that no one has come up with a hard-and-fast definition of what qualifies as excessive celebration. Several players said that what mattered was not the manner of celebration so much as whether a player had earned one.

Hearn agreed. “If you’ve done something that’s worth celebrating, that’s not a problem,” he said. “If you hit 26 [a paltry score] with three darts and celebrate, you’ll be in front of the disciplinary panel.”

One player who has embraced Hearn’s call for more flamboyance is Peter Wright, who competes under the name Snakebite. He sports a colored mohawk and adds to that for matches — his wife paints a snake on one side of his head and the flag of the country where he’s competing on the other.

He said the PDC should give players a long leash when it comes to merrymaking. “Otherwise we’ll all go up doing the same thing, all robots, no celebration, and people won’t watch it anymore,” he said.

Like most minor spectator sports, the popularity of darts tends to rise and fall with the caliber and charisma of the top player. Currently, the dart world is dominated by Michael van Gerwen, considered by many to be the best player ever and who is known to play to the crowd. But even he gives Hearn some of the credit.

“Barry Hearn is the man,” said Vincent van der Voort, a veteran Dutch player, “and if he likes it that everybody’s over-celebrating or whatever they do, then everybody’s going to do it.”