Devon Larratt is not a braggng man. He’s not here to show off. But the above video of him defeating Hafthór Júlíus Björnsson—a.k.a. the mountain of a man who plays The Mountain in Game if Thrones—has gone viral, and so, when we get him on the phone, Larratt wants to make something clear: You are not seeing top-notch arm wrestling there. “The worst thing that can happen is I break this dude’s arm, which I really didn’t want to,” says Larratt, the reigning World Armwrestling League heavyweight champion. “I was trying to find a way to pin him without blowing his arm.”

Here’s the scene: It’s this past Saturday, at an Ontario-area event called Wally’s Classic. It’s like a convention for strong dudes. There’s axe-throwing, CrossFit, strongman competition, arm wrestling, all that good stuff. Björnsson was the guest of honor. Larratt was there holding a kid’s competition, but also had an arm wrestling table available for any adults who wanted to give it a shot. “Hafthor wanted to play around a bit,” Larratt says. So the guys squared off. Someone filmed it.

Here’s what you’re seeing: Björnsson is standing straight up, and trying to win purely on the strength of his arm. That’s not how this game is played.

The rules for professional arm wrestling are pretty simple: Opponents start in the center of the table, with their thumb knuckles showing, wrists straight, and shoulders squared to the table. Then it’s go time. Competitors are not allowed to lift their elbows off the table, and no part of their body can make contact with their arm. But beyond that? “Any pressure you want to do with your hands and arms is encouraged,” Larratt says.

That’s why Björnsson went down so fast. He tried using his arm. Larratt used his whole body.

So what would have happened if Björnsson put his mighty weight into it? On that day, Larratt believes he would have still prevailed. Arm wrestling isn’t just about shifting weight; it’s a game of strategy. “Arm wrestling is a miniature martial art,” he says. “You have many choices and angles you have to work with. A good arm wrestler can feel in his hand where an opponent is weak or strong.” Larratt wins because he remains flexible, he says: He feels out an opponent and tries out different strategies.

Let’s say Björnsson spent a few years training to be an arm wrestler. Then what? “If he was a seasoned arm wrestler at that size, he’d be amazing,” Larratt says. “Without question, that dude has the genetic makeup to be a champion in probably any athletic discipline he puts his mind to.”

So, could Larratt beat a well-trained Mountain? “That match could look totally different,” he concedes.

Here, for what it's worth, is what the champ looks like in real competition:

Photos by YouTube