The competitors stand rigidly upright with their hands behind their backs, waiting to absorb a brutal slap to the face.

When the open-handed blow is delivered, there’s a sharp sound and the reaction can be dramatic. Some fighters barely move, while others stumble backward or fall to the floor. Some are knocked out.

It’s a craze that started in Eastern Europe, with a few viral breakout stars finding fame on YouTube.

Now UFC President Dana White is selling slap fighting in America as the next big thing in combat sports, putting his money and the resources of one of the world’s foremost mixed martial arts organisations behind the Power Slap League. 

“It’s a home run,” said White, who is among several UFC officials involved in the league.

Some slap-fighting beatdowns have gone viral, including a video from eastern Europe showing a man who continues to compete even as half of his face swells to seemingly twice its size. Such exposure has led to questions about the safety of slap fighting, particularly the risk of chronic traumatic encephalopathy, or CTE, a degenerative brain disease believed to be caused by repeated blows to the head.

In the US, the Nevada Athletic Commission has sanctioned the league for competitions in Las Vegas. A former chairman of the commission, which regulates combat sports in Nevada, says approving the league was a mistake.

Chris Nowinski, cofounder and CEO of the Concussion Legacy Foundation, agrees, calling slap fighting “one of the stupidest things you can do.”

“They’re trying to dress up a really stupid activity to try to make money,” Nowinski said.

White and the competitors remain unfazed, comparing commentary on slapping to the negative reaction the UFC faced in its infancy more than 20 years ago.

“I think it’s definitely overblown with the topics of CTE and the damage that we’re taking,” said Ryan Phillips, a Power Slap League fighter. “I think a lot of people still just don’t understand that it’s still a slap.”

White said he believes slap fighting will follow a similar trajectory to mixed martial arts, which the late Senator John McCain referred to as “human cockfighting” in 1996, when the UFC didn’t have weight classes or many rules. McCain’s criticism helped force the organization to become more structured, leading to its widespread acceptance.

White said the ratings of the TBS reality show “Power Slap: Road to the Title” bear out the early popularity of what to many is still a curiosity.

White said he realized there could be a market for the sport in the US when he clocked the millions of YouTube views of slap fighting videos from eastern Europe in 2017 and 2018. The videos were often poorly produced, the slap matches unregulated. 

White became convinced that fights with written rules and shot with professional video equipment could convert many internet viewers into dedicated, paying fans.

The Nevada commission gave slap fighting some much needed legitimacy when it unanimously sanctioned the sport in October and a month later awarded White a license to promote it.

But White’s enterprise was hampered when he was captured on video slapping his wife on New Year’s Eve. White apologised, but has acknowledged it damaged efforts to get the league off the ground. 

But White is charging ahead. Three qualifying events have taken place at the UFC Apex in Las Vegas, ahead of the 11 March telecast on the streaming platform Rumble in which champions will be crowned in four weight classes.

How slap fights work

Power Slap fights are typically three to five rounds. The fighters take turns hitting each other in the face with an open hand, and those on the receiving end stand with their hands behind their backs. A fighter has up to 60 seconds to recover and respond after receiving a blow. Fighters can earn up to 10 points based on the effectiveness of the slap and the defender’s reaction.

Fights can end in a decision, knockout, technical knockout or disqualification, such as for an illegal slap. All slaps are subject to video review. Each event has two referees and three judges.

Also present are a supervising doctor and a physician or physician’s assistant, plus three EMTs and three ambulances. White has touted the safety record of the UFC, but has not talked specifically about injuries in the Power Slap League.