Zone 2 ultramarathoners --> monster 5k runners?

“Typically very slow.” To what standard are they very slow? UTMB winner tom Evans is 13:41. Walmsley is 13:34. Do you mean the average ultra runner? Why do we all need to be super fast at the 5k anyway?

I meant "ultra runner". Super fast relatively speaking-- sub 14 I would say is super fast..

I meant "average ultra runner". Sub 14 is super fast. Those guys are a rarity.

I don't think Jim ever ran 13:34. Let's not get ahead of ourselves here. His PR is more like 13:50s at best:

worldathletics.org

Jim WALMSLEY | Profile | World Athletics

Jim WALMSLEY, United States - Marathon

Link:worldathletics.org/athletes/united-sta...

Didn’t Goggins run sub 4 at the Olympics ? Finishing 3rd behind kofluzi and Max Choi ?

...it's a stupid question

Why is it stupid? Can you explain?

keyword: specificity.

As a 100k or 100 mile specialist, you're running a minimum of 200km a week if you're taking it seriously, and probably more likely 250km. Try doing that for a month and then rock up to the track for an interval session and see how your legs feel after the first 2-3 800s. You can't train (properly) for 100km races and 5km races at the same time.

Understood. What I meant was, if an ultramarathoner decided to drop the ultra training for say 6 months, and focus on 5k races for example, could they then be absolute beasts at 5k b/c of their huge aerobic engine?

Can you explain your reasoning a bit more?

“Zone 2 training” has been the dominant form of training for runners for over 60 years, regardless of event, but 5k training is a lot for than just adding “a bit of speed work” to your easy volume.

Mostly though, it comes down to talent. 5k performance is highly limited by your VO2max, which doesn’t respond much to training after a few years (unless you lose weight, which improves relative VO2.) Longer distances are more about fractional utilization of VO2, which responds to training more slowly. That’s why people tend to move up in distance. You can bang your head against the wall for years trying to shave seconds off your 5k, or you can shave minutes off your marathon…or hours off your 100-mile time. (Case in point: a 15:30, which is barely a D3 time these days, is “aerobically equivalent” to a 2:30 marathon, but very few 15:30 guys ever crack 2:30.) No disrespect intended to ultrarunners (they are insanely tough), but the main reason they aren’t better at 5ks is because they don’t have the talent.

100 miles is ~4x further than a marathon and ~30x further than 5k.

Saying “Bekele was so fast he would have dominated if he ran ultras” is the same as saying “Bolt was so fast he would have dominated if he ran the 5k”.

Saying “Walmsley has to run ultras because he’s not fast enough for the 5k” is the same as saying “Jakob has to run the 5k because he’s not fast enough for the 200”.

Why is it so hard for people on these boards to accept that they are completely different events (almost completely different sports) that require different physiology and different training?

FWIW, I ran 14:35 for 5k and 2:22 for a marathon, but regularly lost in ultras to guys who probably never broke 16:30 or 2:40.

For aerobic engine, 5k (and 3k) guys actually have bigger aerobic engine, as you can run at vo2max pace for 7-11 mins (for a world class guy, that would be 3k-5k).

What ultramarathoning requires is muscular endurance, the ability to run in a glycogen depleted state while navigating technical trails as well as fueling. I know a guy who places top-20 in UTMB, beating a lot of sub 2:30 and even some sub 2:20 marathoners, but his 10k PB is barely under 36, and he has never run a 5k faster than 17. Its a completely different beast. That's why I laugh when people say Kipchoge will dominate ultras. He may dominate in stuff like Comrade, but I would bet against him in something like UTMB.