Lightweight contender Joe Stevenson is considered a master in choking out his opponents. He knows all too well what it feels like to be choked out, as well.
"I couldn't see," Stevenson told ESPN.com, referring to his January loss to B.J. Penn via a rear-naked choke, a maneuver in which the choke is applied from behind with an arm wrapped around the neck.
"I didn't know it even happened. I was crying afterwards."
Stevenson is used to being on the other end of the choke.
Stevenson, who began wrestling at age 11 and learning jiu-jitsu at 13, credits his body structure for his success with submission chokes.
"I have a natural structure for chokes; I am short and stocky," Stevenson said. "If you're a conditioned athlete, you aren't going to go out and feel the demands from the lock. I'm hard to choke because I have been doing it for so long. I know my body's strength. Twenty percent of training is mental, while 80 percent is physical; in a fight, it's the opposite."
To submit Melvin Guillard at "UFC Fight Night 9," Stevenson used what's called a guillotine choke.
"I had my opponent's head trapped under my armpit," Stevenson explained. "I used my forearm and wrist to strangle his carotids. As I raise my body weight, it cranks his head. You choke them in pain until they give."
Chokes first appeared in the pankration event of the Olympic Games in 648 B.C. Pankration bouts were extremely brutal and sometimes life-threatening to the competitors. Rules were minimal in number. In addition, there were no weight divisions and no time limits. The fighting arena or "ring" was no more than 12 to 14-feet square to encourage close-quarter action. Referees were armed with stout rods to enforce the rules against biting and gouging. The rules, however, were often broken by some participants who, realizing they were outclassed by a heavier and stronger foe, would resort to such measures to escape being seriously maimed. The contest itself continued uninterrupted until one of the combatants either surrendered, suffered unconsciousness, or, of course, was killed.
By 200 B.C., referees used rods to enforce the rules, but strangulation remained a major cause of death.
Today, the choke is still a widely used MMA maneuver to stop an opponent. It doesn't require disparity in strength, and it results in no significant injury if properly monitored.
Recently retired referee John McCarthy, who now instructs officials and provides commentary and analysis for The Fight Network's coverage of UFC events, recalls being choked out in his early days as a fighter.
"It's no different than when a guy is knocked out, except he feels no ill effects," McCarthy said. "It's why the first thing a choked fighter always says is, 'What happened?' It's moments that are gone forever."
Chokes are defined by the anatomy they affect. An air choke compresses the upper airway (larynx or trachea), inducing unconsciousness by loss of oxygen to the brain. It can be extremely painful, especially if it involves a "crank" or twisting of the neck. A blood choke compresses the carotid arteries or jugular veins. Without brain circulation, the fighter falls asleep within 15 seconds, but under a well-trained referee's care, neither choke technique is lethal, because brain cells do not begin to die until they have been deprived of oxygen for longer than five minutes.
It isn't always easy, however, to determine when a fight should be halted because of a choke.
"Some are easy if you can see their face and eyes," McCarthy says. "But if the fighter is face down, I look at their hand position and feet. Sometimes I will ask them to give me a thumbs up. It is important to know you can't go after resistance to determine if they are still fighting. It can be like rigor mortis. After they are out, they can remain stiff."
"Some fighters go unconscious and limp from lack of blood flow, while others tense up," he says. "You need a good ref [to know when to stop the fight]."
According to McCarthy, choked fighters don't recognize they are in trouble.
"You'll remember the tension and pressure, but know you don't have a lot of time to get out of it," McCarthy said. "You tell yourself, 'I am not going to stop because I am good.' But it isn't painful, as you just go out. I'll take getting choked out any day. It doesn't do anything to you like a knockout."
I have heard countless arguments that chokes should no longer be a part of MMA. But with a well-trained, well-positioned referee, I can vouch that I have never seen a fighter suffer persistent or serious consequences. It's a sharp contrast to head blows, which can actually damage or kill brain cells.
Dr. Margaret Goodman, a former Nevada State Athletic Commission Medical Advisory Board chairman and chief ringside physician, contributes regularly to The Ring magazine.