A crushing overhand right. A whip-like spinning back kick. A sharp one-two combination. A vicious knee to the body.

One by one, the bodies hit the canvas. Finish after finish. Knockout after knockout. The crowd roared with every impact, every punch or shin that connected.

If you were seated inside Valley View Casino Center last month during GLORY 21, you would have thought you were watching the pinnacle of combat sports. No, the San Diego arena wasn't packed. But those in attendance, including MMA stars like Dominick Cruz, Rafael dos Anjos and Chris Leben, were going gaga.

GLORY kickboxing has been called the most exciting combat sports property in the world. Yet, it's also one of combat sports' greatest mysteries.

Lacking the pedigree of boxing and the sheer spectacle of MMA, GLORY has not achieved popularity in the United States. Ratings have sagged on Spike TV and the organization is still getting over some poor financial decisions in the first half of last year, including a very premature venture into pay-per-view.

For some reason, MMA fans who crave knockouts and violent, stand-up wars have not accepted the very organization -- and sport -- that guarantees both of those things in heaps.

"I think that's gotta be one of the top five most confusing things when it comes to a fight sport," said Pat Barry, who has competed for both the UFC and GLORY.

No one seems to understand why the best kickboxing promotion in the world has not gained a footing in the U.S., least of all GLORY executives. Everyone has their theories, though.

One of the things that seems to be holding GLORY back in the states is its commitment to holding shows overseas. Those events run in primetime in those countries, but air on Spike TV on tape delay in primetime in the United States. GLORY also has a deal with CBS Sports Network for its "Superfight Series," which is essentially a spruced-up version of prelims for its numbered events.

On June 5, GLORY 22 from Lille, France aired live on Spike TV at 4 p.m. ET on a Friday -- without a replay in primetime. The ratings bottomed out at 152,000 viewers. By comparison, GLORY 21 in San Diego drew 488,000.

GLORY CEO Jon Franklin told MMAFighting.com that the live show on Spike from France was an experiment and it obviously didn't work out. The organization still has to toe the line between accommodating international fans and continuing to grow its property in the U.S. Kickboxing is a bigger part of the culture in European countries than it is in the United States. The next event, GLORY 23, is scheduled for Aug. 7 in Las Vegas.

"We love live shows," Franklin said. "Live sports is the original reality show. It always was and always will be. That's really important. But we've got a big fanbase in Europe. We go to Croatia and sell 10,000 tickets."

However, since GLORY 11 on Oct. 12, 2013, GLORY has averaged 460,571 viewers for shows on American soil that aired live on Spike TV. The tape-delay shows (including GLORY 22, which was live in the middle of the day) during that time period have averaged 403,800 viewers, which is not a huge difference.

A bigger problem for GLORY might be that it has yet to develop a marquee star who is a proven ratings draw. While MMA puts a premium on the entertainment aspect of its product, GLORY is very much driven by sport.

"People want to see a show," Barry said. "They can talk all that craziness about [being like] WWE all day and all night, but they want to see Conor McGregor. You know what kickboxing needs? They need a Chael Sonnen, a Conor McGregor. Kickboxing needs somebody who is going to play that Hollywood bad-ass movie role. But the thing is, kickboxers aren't like that. They would never have that.

"In kickboxing right now, they don't have anybody who's annihilating everyone and just talking crazy sh*t non-stop. That would be ridiculous. Unfortunately, that's what it needs. Unfortunately, the fight game nowadays doesn't have anything to do with fighting anymore. Whoever can talk the most sh*t gets the most money. Whoever can talk the most sh*t gets the most publicity."

GLORY is still very much a European company with many of its best competitors, like heavyweight champion Rico Verhoeven, lightweight champ Robin van Roosmalen and top welterweight Nieky Holzken, hailing from the Netherlands, a kickboxing hotbed. None of those men are known for prowess in front of a microphone or camera. Neither are middleweight champion Artem Levin of Russia or light heavyweight champion Gokhan Saki, a Turkey native. All of them, though, are exciting fighters -- knockout artists, even -- inside the ring.

"It is a different market," said Wayne Barrett, one of GLORY's most promising U.S. fighters. "People in Europe love that warrior -- don't say much and go out and fight. Here in America, they want to know who you are. Who am I rooting for? Why am I rooting for you? What's your story? What's the story behind this guy? And that's just what it is."

GLORY doesn't have a single champion from the United States. Perhaps its biggest star here is Joe Schilling, whose popularity is partly owed to also competing for Bellator and having the Knockout of the Year last year against Melvin Manhoef. While not quite like McGregor, Schilling also happens to have an outspoken personality that has resonated with the American fanbase.

"The reality is you have to know these guys to cheer for them," said former superstar pro wrestler Bill Goldberg, who has taken on an ambassador role for GLORY. "It's storyline, it's simple Wrestling 101. If you don't care about the guy, you're not gonna tune to the channel. If you're a purist, you don't give a sh*t who's fighting. You tune in for the art. I believe that most novice MMA fans or combat sports fans that tune in to this on a good night will be nothing but floored with what they see."

Though Schilling competes in MMA, he doesn't want to see GLORY become it. GLORY was in talks to have Goldberg actually compete in a match, which would have certainly drawn the curiosity of MMA and pro-wrestling fans. But Schilling would not be in favor of something like that. He would prefer GLORY didn't water down the product for what he figures would be a short-term gain.

"You want MMA fans to tune in, but what I don't want to see is you putting a guy that walks out of the UFC and into a GLORY fight and getting knocked the f*ck out," Schilling said. "It just cheapens what GLORY is. You're offering world-class kickboxing. But if you start putting MMA fighters out there just to get their names on the card to try to get crossover fans, then you're not providing world-class kickboxing anymore."

Franklin does not disagree, though he obviously wants to draw the interest of MMA fans. It was announced last week that Bellator will work together with GLORY for a hybrid card branded as "Dynamite" on Sept. 19 in San Jose. Schilling and Bellator welterweight Paul Daley will compete in kickboxing matches on the card.

"We're excited to be a part of it and feel honored we were able to put something together with [Bellator president] Scott Coker, who I have the utmost respect for and think is one of the best promoters in the universe," Franklin said. "I think it's a pleasure for us to be included."

In theory, that will put GLORY bouts on a stage where they can and will be consumed by MMA fans. That's the aim, anyway.

"It's just getting people's eyes on it," Goldberg said. "I don't know what it is. I just know that Spike is a great network. I've worked with them before. I just hope they grab a hold of it, along with Viacom, and want to invest in the product and see what it really is."

Most agree that if GLORY got more exposure, especially to the MMA audience, it could excel. Schilling would like to see more commercials and specials on Spike TV. Barry thinks the presentation can get better, since the UFC "feels like a Red Hot Chili Peppers concert" and GLORY is far more traditional.

GLORY had the opportunity to knock it out of the park in June 2014. The organization brought a huge event with three title fights, a one-night middleweight tournament and MMA legend Mirko Cro Cop to Los Angeles. But they made a major misstep by putting the main card on pay-per-view. It reportedly drew just 3,000 buys, a woefully anemic number. In fairness, that was a decision made by the previous regime before Franklin came on board last summer.

"That was a mistake," Schilling said. "Not a mistake, but I think it was an issue. It didn't help. I think if anybody tuned in to watch that Last Man Standing tournament, it would have taken things even higher."

Things are looking up, though, according to Franklin. He said the promotion has cut expenses by 60 percent since he took over last August and they now have a "sustainable model" and are almost out of the "legacy debt" that he was saddled with last summer. Also, GLORY just announced announce a major sponsorship deal with Hayabusa, a former brand tied to the UFC that was forced to leave due to the UFC's contract with Reebok.

Any rumors about GLORY's financial demise or its contract running out with Spike TV are "not true," Franklin said.

"I can't talk about specifics," he said. "It's a multi-year contract. There are some option periods and I think coming out of St. Louis and meeting with the Spike executives I felt more bonded than ever with them. And all the talks we had were talks about the future. I can't say what the deals are going to be, but I think you'll be seeing GLORY on Spike for a very long time.

"From a business standpoint, we're setting this thing up the right way."

That's good news for diehard kickboxing fans. But, of course, that small percentage is not enough for the sport to thrive. The question now is whether GLORY and Spike can figure out how to make the exciting in-ring product translate into cable ratings in the United States. Goldberg referred to it as "a puzzle."

"People want to see knockouts," Barry said. "I tell people, 'You want to see action? You want to see a lot of guys getting knocked out? There's a sport called kickboxing that consists of all strikes. There's no grappling. It's all strikes and you have a much higher percentage of violent knockouts in this sport than MMA.'

"Would you rather watch that than MMA? People go, 'Nope.'"

Is it just because not enough people have been exposed to it? Or will kickboxing always be missing something that would allow it to gain traction with the American audience? With Spike's commitment, we should find out.