Junior mathematics major Adam Brown, who has been slacklining since his freshman year, is part of a group of students trying to bring the unique activity to the campus. The students, who say the sport is addictive, spontaneously meet on McKeldin Mall and put together the nylon webbing tied between trees.

Andrew Bresee clung to a tree branch 8 feet off the ground, his bare foot poised over a 1-inch-wide cord.

His eyes conveyed the steely focus of a hypnotist and he stretched his arms out like a dancer. Taking a deep breath, he stepped out onto the line and into the air.

“Holy s—, this is high!” he exclaimed.

The line dipped and swayed under his weight. Bresee took three slow, painstaking steps only to fall back onto the ground.

“Okay, one more time,” he said, hopping to his feet and climbing the tree all over again.

Bresee, a senior environmental science and technology major, is part of an elusive, disorganized and slowly growing community of “slackliners” — people who walk across lines of nylon webbing tied between trees on McKeldin Mall. Participating students say the sport is addictive and meditative, helping them release stress and develop inner control.

“You have to have your entire mind focused on where your body is in space in order to balance yourself,” said junior mathematics major Adam Brown, who has been slacklining regularly since his freshman year. “We just did a 100-foot line, and it takes like three minutes to go across it one step at a time. So, for three minutes, if you look at something else or think about something else, you will lose your balance … and it causes everything else in your head to get shoved to the back.”

The sport grew out of rock climbing, which uses the same muscles and requires the same level of concentration. Unlike tightropes, slacklines – which are typically one or two inches wide – bend and sway beneath people’s weight. Slackliners typically set up lines anywhere from 15 to 80 feet long and 2 to 12 feet high. On 1-inch lines, some students do simple jumps, 180-degree turns or sit on the line and bounce up and down.

Other students have their own special tricks. Senior biochemistry and music major Caillin Marquardt likes to do handstands, cartwheels and yoga on his line. Junior engineering major Chip Selden plays a game where one person stands at each end of the line and tries to see who can stay on the longest — usually about four seconds, he said.

“[Competition] is fundamentally what it’s not about,” Bresee said. “It’s so self-driven; it’s so much about you setting your own goals. … Even though it’s hard to learn, if you put in the effort, you can pull things out of it.”

Students have been spotted balancing on cords around the campus for years, but the sport only recently exploded in popularity, especially after professional slackliner Andy Lewis performed during February’s Super Bowl’s halftime show.

Still, university slackliners are shrouded in mystery. They have no official student group, and there is no way to know when or where they will appear. To spot them, students just have to be in the right place at the right time.

“It’s a really cool community that you didn’t know existed,” Selden said.

Selden said the sport’s disorganized nature gives participants a lot of flexibility; students can do whatever they want without worrying about safety rules or regulations. Brown said he does not know whether there is a university policy about slacklining, but since the group is so decentralized, no one really seems to care.

“Over the past two years, we’ve been increasing the distance we can walk and how high we can go up,” he said. “At a certain point, I guess someone will have a problem with it, but we’ll just find out when that happens.”

The slackliners said no one has ever been injured and the lines don’t damage the trees. Last year, an “older guy”  — a professor, Bresee assumed — even joined the group on the slackline a few times.

“The most recent encounter we had was a woman police officer who walked by, and I said, I quote, ‘Is it illegal?’” Bresee said. “[She said], ‘I don’t know. Do I care? Not really,’ and she walked away.”

That is not to say slackliners don’t get strange looks from people walking around the campus. Brown said he enjoys distracting entire high school tour groups on the mall.

“We get weird looks constantly,” Selden said. “Everyone will be walking by, turning heads and staring, and people take videos and pictures of us.”

Bresee said seeing who actually stops can be a bit of a psychological experiment. He said many people will just “blow past” them without even stopping to look.

“And there’s some people that stop and look,” he said. “And the coolest people will actually come up to us and ask to try it.”

The slackliners embrace all beginners and usually have a shorter, lower line set up specifically for them.

The sport has its unexpected benefits. Selden said he’s noticed he can keep his balance much better in his daily life. Marquardt said the sport can be used as physical therapy for leg injuries, and he once introduced it to someone with a bad Achilles tendon. But the most significant benefit, the students said, is the calmness they gain through the simple act of balance.

“It’s really helped me work through things a lot of times,” Bresee said. “Just last week, I was really stressed out over exams and papers coming up, and I stood on the line and it was shaking and I was really flustered. But after an hour, I came down — and I just felt awesome, very relieved.”