Caleb Olson, Western States winner, 14:11:25, is a 3:51/8:10/14:18/29:11 track runner

While this all may be true, he will never do that 2-3 month block of marathon training. He runs because he loves moving through the mountains. His interviews post race were very much suggesting that he found even WSER training too limiting to his mountain adventures.

I would also point out that if that 2019 Boston was him, that was very early in his trail career when he was a complete unknown. Probably very early in his time running seriously in any context. He didn't really have trail results that suggested his potential as an elite trail runner until the 2022/2023 timeframe.

two things can be true at once.

of course jakob and kb are/were ridiculous specimens.

of course matt carpenter was a ridiculous specimen.

i would be willing to bet that carpenter's vo2max is higher than both. Kb's is supposedly mid 80s, jakob could be above 90, but maybe not. those two do have running economy and biomechanics that are out of this world. Lot's of cyclists have 90+vo2max but their running economy is crap. going up hill extremely well is less hindered by mechanics and more hindered by power output, weight, and o2 uptake. so it would be expected that some runners are better at metronomic flat running and some much better at uphill. no doubt kenny b and jakob are freaks at both, but plenty of non-GOAT level runners are prob much better bc of high level running economy and crappy o2 uptake (a la frank shorter, famously). the best trail ultra runners are outliers, but not in pure running speed...

be less rojo/letsrunny and more thoughtful please.

One thing to note is that there have actually been a fair number of high 13 5k, low 29 10k NCAA guys who have gone to the trails. Dan Curts (4:00/13:45/29:36) and Mason Coppi (4:07/14:02/29:43) and Christian Allen (13:34/28:26/ multiple XC All-American) are just a few recent examples but Andy Wacker (13:41/29:10) did so back in 2013. They have all had lots of success but they mostly stick to shorter sub-ultra trail races. They also frequently get beat by guys that have nowhere close to their track pedigree. Dan, Mason, and Andy all recently lost to David Norris (an XC skier) at the Sunapee Scramble which was a 9.3mile/3300ft mountain race that functioned as the selection race for the US national "classic" team.

As far as I can tell none of those guys have raced anything longer than a 50k. I think the lesson is that track 10k time does not exactly map to trail success even in shorter races let alone ultras. Running economy just isn't as important and the muscular demands are much higher. Having the engine of somewhat who runs 29:00 flat certainly goes a long way but other people who have developed aerobically off the road/track and are more optimized for the mountains often have more success.

That's right and Killian Jornet doesn't run much from December to March, when he focuses on Ski mountaineering, a form of cross country skiing and climbing combined. If Killian had focused on track in his younger days, looking at his form (in that Norwegian 10km a few years ago, 29:59) I think he might have been a 14:00/29:00 type.

Jim W. was a 13:50x college 5km guy. So was Hayden Hawks (maybe sub 29-min for 10km even). Tom Evans is a 13:40 5km runner. They've all done okay at Western States and other 100-mile races. Or even mountain 100km events like CCC.

5k/10km times certainly can "map trail-ultra" success more often than not given these examples. You say "'running economy' just isn't as important"? It is probably more important in longer ultras! What do you think entails "muscular demands"?

To the one poster speculating that Jim could be a "2:05-2:10 marathoner." That's also just a ridiculous stretch still! He was training super high mileage for ultras and had super shoes already and barely ran 2:15. The ultra training got him 98% of the way there to his top marathon potential. The guy barely broke 14-min for 5km in college and barely qualified for the trials with a 64-min in the half. Maybe he could have run 2:12 at best.
Now he's injured and can't race and is likely past his prime. The Caleb's of the world can easily take down that Western States 100 record if it was a few degrees cooler in future years.

Wondering if any of those 100km specialists like Sorokin (Lithuania) who ran 6:05:00 for 100km, representing 5:53 per mile, or 3:39 per km, (absolute mega monster!!!), and Japanese 100km runners....sub 6:20:00. ...would do well at Western States and other ultras? They're economical and run all day like metronomes, but can they run up and down hills? Muscular endurance...? hmmm...I have reservations ..

I think I should have been a bit more clear but my point was not that fast college guys can't run fast ultras. As you point out there are many examples of fast track people having lots of success. But that being fast at a track 10k does not automatically qualify you for being an elite ultra runner.

As for running economy I had a conversation a while ago with some researchers who have done some preliminary studies on this and the findings seem to indicate that once the trail becomes a bit rough and especially if it is steep that the significance of traditional running economy is significantly diminished. It still matters to some extent of course, but is not longer a driving component of success. I believe this is the reason why there hasn't been the same kind of super shoe revolution on the trail compared to roads. Anecdotally Jim Walmsley said in a podcast recently that he begins to notice a difference in efficiency above a 15% (8.5 degrees) grade which is quite pedestrian for mountainous ultras.

By muscular demand I meant that in trail running, both climbing and descending, you are exerting at a much higher percent of your maximum strength than you ever are in a track race. In that it is closer to cycling. Sustaining effort at high percent of max strength is something that road/track runners never train and could certainly be a reason as to why some make the transition well and others do not.

Chris Myers ran at the club level in college. I think this is him:

athletic.net

Chris Myers - CA Track and Field Bio

Chris Myers - CA Track and Field results and photos on Athletic.net

Open link