One step beyond: the ascent of mountain runner Kílian Jornet

Road and trail running are just different sports and require such a high level of specialization at the very top that crossover is far from trivial. Kilian is still a better road or track runner than 99.999%, but he is very far from being world class in those disciplines. Flat running requires a more refined stride, better foot speed, slightly different muscles compared to going up and down steep trails. Top level track/road runners do not tend to do trail races during their peak years (there is much less money in trail/ultra than track/road), but ones who are just below then do not automatically win trail races.

Trail runs are different for a few reasons. First, long endurance runs take way more time, maybe 16-18 hours for top-tier athletes to do 100 miles, while a fast marathon isn't much over 2 hours. Also, there are typically lots o really big hills, which require more leg strength to run up and down. There's a lot of additional challenges to running in the mountains (rocky / uneven terrain, snow, river crossings, rain, darkness, etc), the pace is typically much slower. Even pros don't often run much faster than 8 minute / mile pace in a long ultramarathon, while Kipchoge can run most of his miles at 4:30 pace - as long as it's a flat road and it'll all be over in a couple hours

He ran the Pikes Peak marathon in 3:27min. The Pikes Peak Marathon course starts here at 6,300 feet, before climbing more than 7,700 feet to Pikes Peak’s summit at 14,115 feet. It then returns to the start. It is on trails (not great ones). It has switchbacks. Kipchoge's course had a total of 18m of elevation gain, and a net of around 5m...it was on roads with corners designed to not slow him down. Kilian's runs aren't just about speed or optimization they are also about significant skill. It's the tortoise and the hare...I don't know Kilian's outright best road marathon time, but I'll bet it would be extremely competitive but not world class. Eliad would win a road 50k (31mi) I'd bet, but I would put my money on Kilian for a head to head trail marathon or a moutnain race, or a 50miler.

As a point of comparison Jim Walmsley holds the outright record at the Western States 100, his pace was 8:30min/mi. He also holds the 50 mile world record at 4:50:08 (5:48min/mile). He ran the US olympic marathon trials this year...he finished 22nd with a 2:15:05 (5:10min/mi pace).

Funny enough, 2:15 seems to be a common marathon time for elite ultra and mountain runners [0]. Those last 15mins are HARD, the last 3min are beyond my comprehension as a person who prefers ultras and mountain races over the road marathon scene. But so is a marathon at altitude with 7,700 ft of climbing. So is a 50 miler at nearly marathon pace. Give them a road marathon, Eliad will crush the other two. A mountain course with tons of climbing and scrambles and choss, I'll pick Kilian. A reasonable but very long course (>50k), I'm going to pick Jim. They are just hard in very different ways. It's like comparing a rally car to formula one car to a le mans car...different optimizations.

[0] https://www.fastrunning.com/training/marathon-training/kilia...

In a nutshell, while they have much in common, the obvious differences correspond to different skills/abilities which don't all translate perfectly.

For mountain and trail racing, you have rough terrain rather than smooth roads; large elevation changes and high altitude rather than flat sea-level races; a generally longer duration; and a much slower average pace.

You can think of road marathons as like Formula 1 car racing while mountain running is more like a race while towing a 2-ton trailer on a rough dirt road. Both events require power and speed, but the kinds of vehicles are quite different. An SUV can produce lots of torque but it would redline far before getting up to 200 miles per hour.

In addition to the other great answer above, it sounds like a minor detail, but the shoes are fundamentally different too.

So much was made of Kipchoge's Vaporfly shoes and how little they weighed, and how much energy they returned during each step. Whereas trail shoes are much, much heavier, have little spring and are generally robust to protect the foot from stones and rocks.

Also, going for 10 hours with minimal food or drink is pretty unusual too. You'll see Kipchoge grabbing a specific drink from a feed station especially for him. Whereas Jornet... 'drinks from a stream if I need it'.

In the same vein take a look at tvmountain, also on YouTube. Little to no talking, almost never any music, just the sound of crampons & the ice axe. I find it strangely relaxing.

Humblebrag :) Good job, that means you were way under the cutoff.