"Building fitness and my personal skills to try to set a time that's perfect for me - the best I could possibly do - that's the motivation. And the best benchmarks that we have of performance on these mountains is what other people have done before, so I use that as a yardstick."
When we speak, it's been less than a week since news started to break that Jack Kuenzle had claimed yet another FKT (Fastest Known Time), this time on North America's highest mountain, Denali. Back home, exhausted but relieved, Kuenzle hasn't had much time to reflect on his latest achievement - dethroning none other than Killian Jornet... again.
The FKT Hunter
Much like a Strava Segment, Fastest Known Times (FKTs) are the fastest recorded efforts on a hike, bike or run. Usually played out in the backcountry, the popularity of chasing down FKTs exploded during COVID, when trail races worldwide were cancelled.
Over the last few years, Jack Kuenzle has forged a formidable reputation amongst the FKT community. Since bursting onto the scene in 2019, the 28-year-old former Navy Seal has hunted down no fewer than 23 FKTs, with 21 still standing (including Mount Hood and the White Mountains 100).
Amongst those FKTs, his time on the 66-mile / 106km Bob Graham Round truly underlined his position as someone to watch. Having bagged the FKT on the Tranter Round (a variation on Scotland's Ramsay Round) just a few weeks before, Kuenzle dethroned Kilian Jornet in September 2022, setting a new FKT for the Bob Graham of 12:23:48 - more than 28-minutes faster than Jornet's previous best.
It was a remarkable achievement for someone who had only decided to tackle his "dream" race after finding cheap flights to the UK, discovering that he had to stay for three months because that was the shortest amount of time he could take out van insurance, and rustling up a team of pacers the night before the attempt due to a favourable weather window.
If this kind of backstory to an FKT Challenge sounds unorthodox, that's because it is.
While many athletes of Kuenzle's calibre turn up with a team to support them through an attempt like this, Kuenzle travels light with few companions. And while his physical preparation for an effort like Bob Graham or Denali is, in his own words, "meticulous", the research and preparation sometimes is... not.
"When I actually got up Denali, I really had no idea what it was going to look like," Kuenzle reflects. "I never stopped to read a trip report, or write it down, or look at the map. I was always like, 'oh I'm gonna go up there. I'll figure it out then'.
"But then I ended up not going up there [to recon the route], and so all of a sudden on race day I was figuring it out on the fly, which was a little strange."
Hitting the heights on Denali
Following his successful attempt on the Bob Graham FKT, Kuenzle shifted focus to the snow. He bagged two ski FKTs during the build-up to Denali - Mount Shasta (02:30:48) and Mount Rainier (03:04:31), honing the techniques and skills required to conquer North America's highest mountain.
Standing at 20,310 feet (6,190m), the recognised route to Denali begins and ends at the airstrip at 7,300 feet / 2,225m. Most attempt the ascent over many days, with complete itineraries taking upwards of 20 days once preparation, laying supplies and weather windows are taken into account. Kuenzle did the out-and-back in 10 hours 14 minutes 57 seconds - 30 minutes faster than Karl Egloff's previous best (11:44:00).
"A lot of people who have climbed Denali maybe have trouble with my time because I'm probably one of the few people who have climbed Denali from the airstrip to 14,000 foot [4,267m] camp with very little gear - just the day amount of gear. Pretty much everybody does the section (from) the airstrip to 17,000 feet [5,181m] with a very heavy load."
But the goal of an FKT is to move fast. Kuenzle took only the jumper he was wearing during this interview, "a pair of three-quarter heated tights and a pair of heated socks. The only thing I put on the whole day was mittens - that was it even up to 20,000 feet [6,096m]. I did put on a parka on at the summit because I was worried about falling, incapacitating myself and freezing to death."
Getting the record is important, but what motivates me is getting a time that is as close to perfect for me.
Moving quickly through near-perfect conditions - save for a whiteout between 9,600 feet / 2,926m and 10,600 feet / 3,230m - Kuenzle had only one moment when he thought it wasn't going to be his day.
"From 12,600 feet [3,840m] I could see the upper mountain, and it was completely inside of a lenticular cloud - it looked awful. I was like, 'there's no way', and I even thought about giving up in that moment and coming back on a different day.
"But then I was like 'oh you know what? I'll just try to see it through', and by the time I got to 17,000 feet [5,181m] that cloud blew out and like the wind died completely. I got very lucky."
But still, he had to push, the shadow of Kilian Jornet's time constantly hovering around him. "I have to be constantly prodding myself to stay on pace.
"A lot of times I'll do something like this and I won't look at my watch, but I was just too curious. I was furthest behind Killian at 11,000 foot [3,350m] camp, and then by 13,000 [3,960m] foot camp I'd probably caught up to him completely.
"I'm constantly kind of like prodding myself, and the higher you go up the more you become limited by breathing, and that makes it tricky. What was really nice was the fact that when we were there, there were so many people on the route above 17,000, and so I would just focus on catching or passing the next group and then I'd catch up to them, and then I'd like you know talk to them for like 15 seconds as I was passing them - that was kind of fun - and then I would just focus on catching the next group. I distinctly remember as I was getting higher that there were less and less people, and then I ended up being the second group to summit that day."
Not that there was (much) time to take in the view. "I had a moment for a second - I should look at my Strava and see how long I actually stopped for. There was a minute where I was like 'oh wow, I just summited Denali - that's kind of cool' and I wrote my name in the snow with my ski pole.
"But when I got on the summit ridge I was surprised about how exposed it was, and basically from there down to 17,000 feet my focus was just on not dying. Time was certainly a distant second."
But while there was little time to savour the moment on the summit - or the descent - there was a moment when Kuenzle realised he had achieved his goal.
"Right before I finished, I started crying a little bit because I knew at that point that I was actually going to get it. But immediately, my brain went to the fact that I had to go back up to 14,000 feet the next day, and I knew how awful that was going to be."
Now back in Boulder, there is one thing Kuenzle is sure about: he isn't going back. "Denali is unique. I think it's the only record that I have where I think if someone broke it I would never go back.
"I'm confident about that for two or three reasons: Number one because I felt it was fairly dangerous, but bigger than that is that it's a huge expense and hassle to get up there, and I didn't really enjoy the expedition lifestyle. The third thing is that there is no way to know what conditions you will have until you do it. I got really lucky."
A future in racing?
Throughout the conversation with Kuenzle there are constant references to races and race days. But you won't find much if you look him up online or search for a race resume. That's because Kuenzle is, somewhat ominously, yet to compete in a trail race. Instead, his race days refer to FKT attempts.
But there are signs his focus is changing.
"I'm just starting to run out of records that have my interest, and that fit my capability. Increasingly I'm going to have to start making things up."
And at that point, he will start to target races. "What I don't want is - because of my personal weirdness - for people to look at me racing something like UTMB as me graduating to racing.
"At some point, I will start racing because I'd like to race against the fastest people, but also because I'm running out of projects."
For now, though, Jack Kuenzle is continuing to pursue perfection. That he can break FKTs without being 'perfect' simply underlines his exceptional talent.