Text the other danish guy · Photos Kimmo Korhonen

In spring 2026 a message arrives through the contact form of a Finnish online underwear shop. It begins: “This is just feedback.” The sender explains that his wife bought him his first pair from the brand as a present in 2019, and that he started wearing them on his runs. Then he gets to the point: “Yesterday I passed 16,000 km of running in your boxers. (I keep statistics on all sorts of things.)” The message is signed with a single letter between two dashes: -m-.

Mika Koskinen is a 58-year-old biochemist from Turku. As a runner he belongs to Finnish Marathon Runners, the club that organises the Kaarina Autumn Marathon every year in Kaarina, just outside Turku.

“I always considered myself a fairly poor runner. Running never felt particularly good, and 10 km seemed a really long way to run, or jog.”

He has his own conclusion about school PE in the 1970s and 80s. “My feeling is that I might have had some potential as a youngster, but physical education back then wasn’t about encouraging you or helping you develop. It was about grading you.”

The spreadsheet is in Excel. His runs are also recorded in Strava and the Suunto app, but Excel is the one he keeps himself. The first row is from 2016. That year he ran 61.5 kilometres. He started keeping records because he wanted to know how many kilometres he was actually covering. The first year’s figures showed, in his words, “that my jogging was more of an idea than actual jogging.” He went out about three times a month, and only when the weather was nice. The following year he logged 186 kilometres. In spring he managed a run most weeks; by winter it had faded away again.

In 2018 he ran 850 kilometres, and the year was, as Mika puts it, “a watershed of sorts.” There was snow early in the year and he skied a lot. In August he joined Vauhtisammakot – roughly “the Speed Frogs” – a running group in Turku, and under coach Mikko Liukka he improved fast. His 10 km had until then been “only just” under an hour. That autumn he ran 47 minutes in a race on Ruissalo island, and later in Kaarina he broke what was then his magic barrier, 45 minutes.

Aiming for sub-three

In 2019 he passed 1,000 kilometres in a year for the first time, finishing on 1,707.5. That year Mika also ran his first marathon, the Paavo Nurmi Marathon in Turku, in 3:43. It felt, he says, “brutally hard.” “I was never supposed to become a marathon runner, but the next year I ran two.”

Since then his best marathon time of the year has stayed under three and a half hours: 3:24 at the Kaarina Autumn Marathon in 2020, 3:19 in 2021, 3:12 in Kaarina again in 2022 and 3:07 in 2024. Last year he ran the Helsinki City Marathon in 3:23:08.

“I was never supposed to become a marathon runner, but the next year I ran two.”

Mika Koskinen

Since the personal best, the goal has been to break three hours. Last year he came close at the EMA Marathon in Jyväskylä: he went through halfway in 1:29, “but my fitness didn’t hold to the finish and I hit the wall in the last quarter.” He finished in 3:11:50. This year he has focused on half marathons and improved his best three times. His baseline is now well under 1:30, and at his fastest he has averaged 4:05 per kilometre over the half. His best road 10 km came this autumn, “a whisker under 40 minutes.”

His weekdays run in the same order from one day to the next. After work Mika drives to pick up his wife from her workplace, which is on the way, and they do the shopping. At home there is laundry and cooking, in his words “a joint operation, each with our own area of responsibility.” Then a quick change into running kit and the day’s session. “I don’t eat until after training.”

He would rather run in the late morning, but work pushes weekday runs into the evening. He does intervals on a straight stretch of road about two kilometres from home, so the run there and back takes care of the warm-up and cool-down. Hill repeats and trail runs are in the forest nearby; in the winter dark he finds his hills on the roads. Weekday runs are five to ten kilometres, on Fridays sometimes 8–14 km at race pace, and on Saturdays a long run of 12–32 km. Sunday is for recovery. “There’s nothing slavish about following the plan,” because there are late meetings and evening commitments. “I try to listen to my body with a sensitive ear, and I take a break if it starts to feel like my legs need to recover.”

The spreadsheet has a second tab called Programme. It holds a 22-week training plan in which the weeks count down to the race and every day has a letter. Pa means an easy recovery run at six minutes per kilometre. Pe is base endurance, five or five and a half minutes per kilometre. M is hills, T tempo, IV intervals and K a race-pace session at 4:15 per kilometre. The intervals start with four 800-metre repeats and build to eight. In the final week the repeats are 400 metres long, and there are four of them.

A race pace of 4:15 per kilometre means a 2:59 marathon. Next year Mika will try to break three hours, “but not grimly, because at this point it’s a balancing act between ageing and performance.”

There is a gap in the spreadsheet in 2023. He logged 1,494.8 kilometres, about a thousand fewer than the year before, and ran no marathon at all. He had had minor overuse niggles before. In 2021 he had to “fight a bit” with a knee and added mobility and stabiliser exercises to his daily routine. In summer 2023 his back became very painful on a run. The pain eased with rest, but even a short run brought it back, and soon it was constant. The occupational health doctor found two bulging discs. Rehabilitation took more than six months of targeted exercises. “Of course my fitness had collapsed, but it came back in the end, once I had the patience to build up slowly.”

The following year brought the biggest number in the spreadsheet, 3,257 kilometres, and his marathon personal best.

A present that stayed in use

Mika describes the underwear column in an email he sent in July. In his spreadsheet, cumulative underwear use is added to the runs “simply as a SUM cell,” as you might expect from a biochemist. When Mika comes to Kupittaa sports park in Turku on a rainy Friday to be photographed for this story, he clarifies that the figures cover only kilometres run. “It doesn’t include any everyday wear, or skiing and cycling, even though it’s always one and the same choice of underwear.” He hasn’t tracked individual pairs. He wears whatever comes to hand, except in races. In races he always wears the short model, because it is the only one that sits well under racing shorts. He hasn’t counted the washes, and he apologises for that.

Some of the pairs he ordered himself, some were presents from his wife. The first pair, the one she bought him in 2019, is still in use, in his words “intact (and washed).” According to Mika, his wife got the idea from television, where the company’s advertising campaign was running that autumn. The gift was “very well liked, and no other underwear has been allowed on a run since – or anywhere else, for that matter.” Mika has had a problem exactly once. It was in 2020, in an extremely hot 38-kilometre trail race, “where the runner himself was completely spent and his running technique had totally fallen apart. The damage was some minor chafing.”

The real question is whether the man holds up

Tommi Lähde, CEO of the other danish guy – a Finnish brand, whatever the name suggests – was struck by Mika’s story. Plenty of other customers have written in to say they have worn the company’s products for years because “these just don’t wear out.” Mika was the first to say he had kept statistics. Lähde emailed Mika to ask whether the story could be told to a wider audience. Mika replied within half an hour: “That’s fine by me.” He has no photographs to prove the kilometres really were run in that underwear. “Though I suppose I’ll just have to give you a sworn statement that I really was wearing TODG boxers on my runs.”

He signs his emails with the odometer reading: “Regards, Mika (16,101 km)”. At the end of April he ran the Aura River night run in Turku, a race that appears in the spreadsheet every year. His time was 42:03 in 2019 and 41:16 in 2021. This year’s 41:08 is the best in the series. At the end of July, in the last week of his summer holiday, the reading stood at “16,969 km as of this morning’s run.” The kilometres pile up fast. The season ends with the Kaarina Autumn Marathon, but there Mika wears a marshal’s vest instead of a race number. “Traffic control and that sort of thing.”

Mika has described the Kaarina Autumn Marathon as an event that is “not exactly the size of the Barcelona Marathon.” The club’s chairman, Janne Klasila, corrects him: “Fortunately we’re not the size of Barcelona – we’re bigger. We have a warm heart, and we put on an event in our own style, with the runner and the running community at its centre, not money and commercialism.”

Measured by participants, the Autumn Marathon is large by Finnish standards: this year there were about 1,200 runners, up from 718 the year before. Every spring the club also organises the Kaarina Track Ultra, known as KARU, which in 2025 hosted the Finnish 100 km championships.

For Mika, running has become a way of life, and it keeps him able to do the things he needs to do. “Running has shown me that distances don’t matter.” He finds the effects of ageing hard to judge, because his performance is still improving. “The older you get, the more you have to think about mobility work and the like, and you have to listen closely to how your body feels.”

“Fortunately we’re not the size of Barcelona – we’re bigger.”

Janne Klasila, Finnish Marathon Runners

He has one more thing to say about school PE. “It may be that we lost some promising talent back then, but I suppose things are better in that respect nowadays.”

And do the boxers hold up?

On 27 September an EU directive took effect that bars companies from making sustainability and durability claims in their marketing that they cannot back up. In August, Tommi Lähde proposed a swap: Mika’s first pair would come back to the company, and he would get new ones in their place. The pair that had been in use for seven years would go to an independent laboratory for testing, to find out what makes them last and to see what has happened to them. Mika replied. Attached to his email was the spreadsheet, and a clarification: “The data certainly doesn’t prove that the underwear lasts those 16k, only that my backside and groin have been doing fine in those boxers for those 16k.”

In his first message he wanted to report that he had passed 16,000 kilometres. With this one he wanted to make sure the story would not claim more than can be proven.

The email ends: “Where shall I send that historic pair number one?” ■

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