Updated

By Peter Rutherford

(Reuters) - It has been branded "human cockfighting" by Senator John McCain and bloodlust unbound by its critics, but mixed martial arts has evolved from 'no holds barred' brawls to become one of the world's fastest growing sports.

Popularized by the Ultimate Fighting Championship in the United States, MMA is a fusion of fight styles that melds the stunning strikes of boxing and muay thai, the sleek submissions of Brazilian jiu-jitsu and the devastating power of wrestling.

It has fought hard to gain credibility, regulatory backing and global appeal by introducing a comprehensive list of rules, stringent doping procedures and embarking on a educational campaign to win hearts and minds.

Now sanctioned in more than 40 U.S. states, the sport is experiencing explosive growth in viewership and participation. Its top athletes are winning mainstream recognition, hefty salaries and lucrative sponsorship deals.

George St-Pierre, the UFC's welterweight champion, inked a multi-year deal with sports apparel maker Under Armor Inc in November and earlier this year became the first MMA fighter to sign with Gatorade.

MMA gyms are springing up worldwide and the UFC is staging events in Europe, Canada and Australia.

Chatri Sityodtong, managing director at the new Evolve Academy in Singapore, said that MMA's massive growth lay in a primal fascination with combat -- "a reflection on humanity, the caveman instinct."

However, it did not deserve its reputation for violence, he said.

"This is the greatest misconception about the sport of MMA," said Chatri. "If it was such a violent, dangerous sport the safety record should be worse than boxing .... worse than skydiving, worse than all these other adrenaline sports. Yet it's safer."

'BLOOD AND ILLEGALITY'?

While boxing has a far longer history, the 'sweet science' has a much poorer safety record, with studies in the Journal of Combative Sport putting the number of ring-related deaths at more than 10 per year worldwide.

The death of Sam Vasquez in 2007, however, is the only fatality from a sanctioned MMA bout in North America, though there have been three other deaths in Mexico, South Korea and Ukraine.

Boxing and MMA have an uneasy relationship, due in part to their battle for pay-per-view revenues.

WBC chief Jose Sulaiman told Reuters in a previous interview: "(MMA) is fed to those fans who like aggression, blood and illegality. They are not boxing fans. Boxing fans have class."

Thai Chatri, who trained at the world-renowned Sityodtong muay thai gym growing up and holds an MBA from Harvard Business School, pointed to the numerous former Olympians who have switched to MMA as an example of the sport's growth and safety.

"If it was all about violence it would be like two animals fighting. But it's not," he added.

"These are professional athletes who love this stuff, dream about it all day long and give their entire lives just to be able to showcase their abilities."

MARTIAL COMBAT

Chatri said MMA was primed to take off in Asia after having become the third most watched sport in the United States, although other sources suggested the figure referred to viewers within the male 18-34 demographic.

"We blew through our three-year financial goals in three months, so there's strong interest in Singapore," he added.

"We are at the beginning of the MMA revolution in Asia."

That "revolution" will take a step forward next year with the launch of 'Martial Combat', a series of MMA events to be broadcast across Asia by ESPN Star Sports (ESS) and staged at Singapore's S$6.59 billion ($4.69 billion) Resorts World Sentosa.

ESS said the first event, scheduled for May 14-15, would feature top fighters from Asia and around the world and would be broadcast in 24 countries around the region.

Victor Ciu, director of the events management group at ESS, said they had been working for two years to create the event and had made safety their top priority.

"When we first created the X Games it was full of very similar questions: 'Is this really a sport? Is it dangerous?'" Ciu told Reuters. The X Games feature sports such as snowboarding, skateboarding and BMX.

Ciu said the event that while MMA would find it tough to replace soccer and cricket as Asia's top sports, there were definite growth opportunities.

"We think that the really exciting opportunity for the sport is not with the 'diehard MMA fans' -- those people will watch it regardless. What we want to do is ... bring the sport to people who enjoy competition, who enjoy the genre of 'fight'.

"The objective is to make this entire event an entertainment show. In the same way as if for a concert or a musical, you leave with a positive experience."

(Editing by Ian Ransom)