Before Chicago stuntman Ethan Swanson leaps between buildings, he clears his mind.

“If you’re going to be trying something like this, your worst enemy is yourself. If you doubt yourself at the last second and try to pull out, that can do more damage than actually going through with it,” he said.

Swanson, 24, of Lakeview, is a trained gymnast who frequently rock climbs and calls himself an urban gymnast. He regularly heads to the tops of apartment buildings and abandoned A-line homes, hopping from roof to roof, with a camera strapped to his head.

Swanson shot his most recent video alone, over a chilly weekend in April, after scouting out the location near the Armitage CTA Station in Lincoln Park. He said he planned the jump featured in the video after being contacted by representatives of GoPro, a company that makes portable video cameras and videos known for their precarious, daredevil angles, earlier this year.

Swanson said he is not allowed to discuss the terms of his agreement with GoPro, which published a promotional video featuring his footage on the company's Youtube channel Wednesday.

The video, which features a CTA El train rumbling through the background of Swanson’s jump, was on the front page of the link-sharing website Reddit Wednesday afternoon, where Swanson was answering questions from curious viewers.

“People ask, ‘What goes through your head when you do a jump like that,’ and the answer is, surprisingly little,” he said. “But beforehand, there's definitely a lot that I think about.”

As Swanson does before attempting most jumps, he checked out the stability of each roof and surface he planned to place his weight on, and measured the distances between them. Then he stopped by a gymnastics gym in the North Center to practice the jump, using gymnastics gear spaced apart to simulate the buildings.

“First, I see something I think would be cool and doable for me, and second I make sure it is as safe as it can be,” he said. “Obviously, it’s inherently dangerous. I try to walk it and just make sure that everything is sturdy, and that I’m not going to be falling through a roof or stepping off a ledge that will give way.”

Swanson, who works as an actuary and practices his jumping in his free time, didn’t walk away from his April jump completely unscathed.

“On my left side I had shin-guards, two on my leg and two on my arm, so that when I was sliding [down the roof] it wouldn’t just cheese-grater me, but all the in between areas got torn through pretty quick,” he said.

He also bruised both of his heels on his landing, but, he added, “I didn’t break anything.”

When asked whether his stuns are legal, Swanson said he’s not sure.

“Whenever I’ve been confronted by police it’s been like, ‘Hey, cut that out,’ and I say OK and I come down,” he said. “But I mean, whenever if I go anywhere, if there are no trespassing signs, I don’t go.”

Swanson said because of the risks involved in his hobby, he almost always goes out for a jump alone, without a spotter, and he doesn’t know anyone else in the city who shares his hobby.

“I don't like the thought of dragging somebody else into it,” he said.

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