LAS VEGAS (AP) — The state commission that regulates slap fighting — in which opponents take turns striking each other in the face — attempted Wednesday to address a critical question for the budding sport: What constitutes a legal slap?

Competitors in the Power Slap League must deliver only open-handed blows and must not hit opponents below the chin, according to amended rules approved by the Nevada Athletic Commission that seek to make the matches safer.

The commission originally voted in October to sanction slap fighting, asserting it wanted to prevent unregulated matches and ensure competitors are safe. However, commissioners were concerned the rules weren’t specific enough.

“So, these guys want to get serious about the sport and it sounds like they do,” said Anthony Marnell III, chairman of the commission which also regulates boxing and other combat sports. “It sounds like they want to evolve the rules. We as a commission need to keep up with them at lightning speed on how we’re going to review this. And we have to have a process for it because there’s going to be controversy.”

In November, the commission also approved UFC President Dana White’s license to promote the Power Slap League. White and other UFC officers are involved in the league, but the UFC does not operate it.

Power Slap is being featured in the TBS show “Power Slap: Road to the Title.” The first four episodes averaged 275,000 viewers.

However, many competitors exhibited apparent concussion-like symptoms, raising safety concerns about the competition.

Power Slap President Frank Lamicella told the commission Wednesday there have been “no major injuries” among the 25 matches the commission approved.

Any slap that doesn’t meet the criteria will result in disqualification, and every strike is subject to video review. The review official has the final say over whether someone is disqualified.

Marnell was especially concerned about replay guidelines being followed.

“I think we have to take this sport, whether you like it or not, just as serious as we take the $20 million, $100 million boxing match that we’re responsible for,” Marnell said. “We need a process for this because the way that I see this going, and I haven’t been to one yet in person, but watching this you are going to be reviewing every single slap. The clamp down on the carpal bone hitting the cheek first has got to be zero tolerance. It’s over at that point.”

Lamicella said the league is using the same replay equipment as the UFC. “We’ve taken the MMA rules and adjusted it for slap, and it is evolving and will be evolving even more,” Lamicella said.

White promoted the TBS show in an interview with Front Office Sports last week. He acknowledged in the interview that a video of him and his wife slapping each other during an argument on New Year’s Eve at a Mexican nightclub didn’t help in his efforts to promote the new sport. He called the timing “ironic and horrible at the same time.”

The commission has approved upcoming Power Slap events March 9 and 11 at the UFC Apex in Las Vegas. The UFC Apex plans to install a 1,000-seat arena, according to the Las Vegas Review-Journal.