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Running’s most intense hill workout: Kilian Jornet’s ridiculous one-hour challenge

Jornet shares his toughest training session: run a vertical kilometre followed by a flat 10K, all in less than an hour

Photo by: Instagram/kilianjornet

We don’t expect you to try this at home, but it’s too impressive to ignore. On Monday, Spanish ultrarunning champion Kilian Jornet shared one of his most intense training sessions on Instagram. Dubbed the VK10K, this challenge sees Jornet run a vertical kilometre (meaning 1,000m of elevation gain) followed by a flat 10K. This sounds difficult enough, but he adds a time factor to it and attempts to run the whole thing in less than an hour. Like we said, don’t feel pressured to try this.

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One of the hardest training session I do is what I call VK10K. Concept is simple: to run a vertical kilometer, run down easy and run a 10K flat. Normally I do a “easier” version of 700m + 7K, today I did pretty much at full gass. I started with the VK speddy since from 700 to 800m this uphill has something like 100m of distance with a couple meters down and flat. ( that’s a pity because I believe if it wasn’t for those meters it could be a very fast place for a VK!) I reach the 1000m in 29’57”. Easy way down and then I started the 10K on a semi conservative pace trying to be close to 3’/km. The hard thing is to push with the legs still “heavy” from the lactate of a VK. Last 2K I gave everything to close in 29’42”. So almost 1h (59’39”) with blood taste in the mouth and bottle legs 🤪 . 2nd picture by @mzolad1986 . And obviously the heart rate was waaay higher than that, more like 185-195 for all the VK. That’s a wrist measurement and I have always the watch not tight 😉

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Jornet has won so many of the biggest ultramarathons around the world, including the Western States 100 and the Ultra-Trail du Mont-Blanc. He is without a doubt one of the greatest ultrarunners of all time, and this workout shows why. For most people, this wouldn’t even be on their radar as a one-off challenge, but this is an established training session for Jornet. In his Instagram caption he explains how the run works.

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“Run a vertical kilometre, run down easy and run a 10K flat,” he writes. He at least has some break between the intense climb and the quick 10K effort, but running down a steep grade will tire your legs out, too. He says he usually does an “easier” version of the VK10K, with 700m of climbing and a 7K flat run instead, but on Monday he ran true to the challenge’s name. 

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When it comes to training we often trend to look to the exception and overlook the rest. We focus on that 1% of what top athletes do, those supermegasessions, the flavors of the diet, the meditation exercises or the pre-race routines… those anecdotal things can give marginal gains and are often easy to achieve, because it belongs in a big part to technology access or it demands a short term motivation. But we often forget about the importance of the other 99%, those boring and simple things and sessions, because they’re not fancy to explain, they seem to simple to do, but in reality they’re the hardest to achieve because they demand long term motivation (years) patience, focusing on process and repetition. At the end of the day they’re the ones that makes real progression: Lots of hours during many years at slow pace, lots of hours during many years at moderate pace, lots of hours during many years at fast pace. To recover and eat well 24/7, to not do too much outside that. To keep it simple is sometimes the hardest.

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He says he started out “speedy” on the vertical kilometre to make up for about 100m of flat and downhill terrain three-quarters of the way through the climb. “That’s a pity, because I believe if it wasn’t for those [flat and downhill] metres it could be a very fast place for a VK,” Jornet adds. He completed the 1,000m climb in 29 minutes and 57 seconds, giving him a hair over 30 minutes to complete his 10K if he wanted to accomplish the VK10K in less than an hour. 


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He writes that he started the 10K “on a semi-conservative pace,” trying to hover around three minutes per kilometre. In the final 2K, he “gave everything” and finished the route in 29 minutes and 42 seconds, bringing his official vK10K time to 59 minutes and 39 seconds. He says the effort caused him to taste blood in his mouth, and his heart rate was understandably skyrocketing throughout, but he made it through with a quick result. 

While most people in the running community can only dream of running a VK10K as quickly as Jornet, you can still run a variation of the workout. Try a V5005K (500m climb followed by 5K flat) or even a V2002K or V1001K. It’s all about challenging yourself, and who knows, maybe you’ll really like the workout’s intensity. 

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