It's a sport that requires exceptionally strong fingers and a stomach for heights.
Bouldering is a form of rock climbing, except there are no ropes or carabiners. Instead, athletes must rely on their own physical strength, problem-solving skills and a bag of chalk dust.
If things go wrong, a large crash mat sits at the base of the wall to prevent injuries from falls.
The best in Canada are gathering in at Altitude Gym in Kanata this weekend for the Open Boulder Nationals.
Professional "route setters" have been busy fastening toe and handholds to the gym's towering walls to challenge the climbers coming to compete.
Competitors including Ottawa's Samuel Tiukuvaara, 22, will try to determine the best route to the top.
Skin in the game
Tiukuvaara, one of three local competitors taking part this weekend, climbs at the gym four to five times a week, for three hours per session. In between climbs, he lifts 65-kilogram weights — with his fingertips. On his "off days," he runs and stretches.
One of the biggest challenges in bouldering is "skin management," said Adrian Das, Tiukuvaara's coach.
"There's a lot of friction on the holds, and that wears away the skin. Athletes really have to manage their skin well so that … they're not bleeding. That would prevent them from climbing at their best."
Bouldering continues to grow in popularity. According to Climbing Business Journal, an industry publication, the number of commercial climbing gyms in Canada nearly tripled over the last nine years, soaring from 41 in 2010 to 115 in 2019.
Sport climbing is making its debut at this summer's Olympic Games in Tokyo. It's a combined three-event format that includes bouldering, lead climbing and speed climbing.
And increasingly, it's not just for weekend climbers, according to Das.
"In the past 10 years we've really seen a lot of climbers consider themselves more like athletes and not just recreational rock climbers. So the mentality of athleticism is applied to rock climbing."