I remember the day at Smith Rock, Ore., when I became mindful that sport climbing — a relatively safe and user-friendly genre within climbing — has a dark side.

I was a teenager watching a 30-something hardman about to attempt a difficult overhang called Power (5.13b). The hardest move involved a shallow, one-pad-of-one-finger pocket into which he could barely stuff his digit.

As he sat in the dirt before tying in, he pulled out a little kit full of pills, files, Superglue and God knows what else. Dumbfounded, I asked, “What’s that for?”

Between puffs of a cigarette he smiled and shook his head — his eyes never leaving his fingers. “You’re too young to understand,” he spat.

I silently watched the wiry veteran mutilate his middle fingertip with a metal file. He shaped it into a sharp talon, then covered it with glue so it would fit deeper into the tiny pocket. He failed on Power that day, but he forever changed my perception of sport climbing.

Boulder’s Christian Griffith butchered his fingers the same way in order to climb Chouca (5.13c), one of France’s most difficult routes in the 1980s. But he lightened up the dark side one shade further by attempting the route wearing only underwear.

To weigh as little as possible, of course.

Boulder’s Matt Samet once spiraled down sport climbing’s dark side by starving himself in order to climb harder. He’d have coffee for breakfast, an apple for lunch and 20 fat-free Saltines for dinner. Four packets of sugar-free hot cocoa washed it down. “I could do this for three or four days before freaking out and going on an epic junk-food binge,” he warned. “This is not a recommended approach for an athlete.”

The root of sport climbing’s dark side, I’ve learned, lies in the obsessive psyche of its players.

Between 1992 and 1994, all-around climber Randy Leavitt established a 5.14a he called Planet Earth at Arizona’s Virgin River Gorge. He was rooted in San Diego during the week — 450 miles distant. Nevertheless, Planet Earth consumed him.

“I even built a replica of the crux on my home wall using dental impressions of its pockets,” Leavitt said.

By March 1994, after 28 days over several seasons, he made its first ascent. Along the way he’d racked up 25,000 highway miles — enough to circumnavigate planet Earth at the equator.

Closer to home, Boulder’s George Squibb fully dark-sided on The Crew (5.14b), one of Rifle’s hardest routes. In the spring of 2002, the first 30 feet of steep, hard pocket climbing were wet.

Nobody attempts wet 5.14.

But Squibb was so obsessed with The Crew that, rather than acquiesce to seepage, he took a trip to the hardware store. Naturally, he bought a blowtorch.

Before every attempt that spring he winched up and torched the wet holds. Then, he lowered quickly to the ground, got his rock shoes on and started climbing.

“There was only a 15-minute window of dryness before the holds started seeping again,” he said.

Squibb finally finished The Crew in October 2003 after more than 60 attempts … and several propane canisters.

The dark side of sport climbing presents in ways too numerous to detail. One of my friends convinced himself that hand washing ruined his callused skin, so he bought a pair of rubber gloves to wear in the shower.

I wonder what his wife thinks about that.

Other climbers I know chew gum instead of eat; they shave their thighs and glue sticky-rubber kneepads to them; they re-texture glassy footholds with hydrochloric acid; they tote enormous, fake rocks to the cliff and stash climbing gear under them to save energy on long approaches.

Since that distant day at Smith Rock, my own sport climbing dark side has manifested in crash diets, cigarettes and climbing rubber glued to my body. I may have been young back then, but I’m pretty sure I understand the dark side. To be certain, I one-upped Griffith’s 1980s audacity by climbing Boulder Canyon’s Stoner Homeland (5.13a) –completely naked.

Contact Chris Weidner at cweidner8@gmail.com