The CrossFit Journal -- (http://journal.crossfit.com)

At 13, Ryan O'Rourke decided to try CrossFit as a way to improve at hockey.

"I wanted to play in college more than anything," he says. "That's what ... I dreamt about."

The plan changed when he rowed 2,000 meters in 7:17.

"To row those kind of times, you've gotta be willing to suffer," explains Markus Riggleman, owner and head trainer at CrossFit Lehigh Valley in Pennsylvania. "And to see that he—even at 13—was willing to ... go there was cool."

Today, at 17, O'Rourke is the 2013 Crash-B junior men's heavyweight world champion on the strength of a 6:02.4 2K.The 17-year-old is making preparations to row at Stanford University.

"Before I came to CrossFit, I never heard of rowing," he says. "And now it's my passion."

The teenager advocates CrossFit to fellow rowers.

"For most rowers, it's just erging, and that's why I think a lot of rowers have trouble getting their times down, 'cause they're not strong," O'Rourke explains.

Right now, he rows about 30,000 meters a week, at least.

"But I incorporate CrossFit, too," he adds. "You get to throw in different movements and have fun with it, whereas if you just erg, you're gonna go crazy."

Video by Mike Donofrio.