[donquichotte]

It's an interesting question, but only looking at energy expenditure probably does not cut it.

I hike a lot and started running races in alpine territory (e.g. this one [1]) about a decade ago and think if you take into account fatigue (mental, muscle, tendons) and exposure to the elements (sun, rain, wind, snow), a light running pace can definitely make you arrive at your destination less exhausted than walking the same distance, given that you can move confidently in the given terrain.

So it is a multi-dimensional optimization problem (as opposed to only optimizing for energy expenditure) and very dependent on how comfortably you can move at the given velocities.

[1] https://www.youtube.com/watch?v=o-12ghcODMM

[fire_lake]

Having done some light ultra events myself I have definitely found that going faster can be less tiring overall because you reduce overall duration - less sleep deprivation, less time on feet, etc.

[Bomboclaat1]

Less time on feet but under a bigger strain with less efficiency which will make you more tired. It's the same for all of these. >(sun, rain, wind, snow)

You are are not as long in the sun but you are longer in the sun under a less efficient energy expenditure. You will sweat more because your are not in an ideal window.

If you look at the Ultra events with 100+ Miles and tons of elevation gain, even the winners have an avg pace of a fast walking speed. There are some hikers who only hiked these events and got very good results.

The more you weight the further the efficiency goes away. Even the top runners only walk the steep uphills. And in long races with lots of elevation gain at the and they are walking all hills. It's exactly because it becomes so inefficient even for lightweights

[PaulDavisThe1st]

> If you look at the Ultra events with 100+ Miles and tons of elevation gain, even the winners have an avg pace of a fast walking speed. There are some hikers who only hiked these events and got very good results.

Sorry, but this is totally incorrect. The record for the Western States 100, which has nearly 19,000' of elevation gain, is just over 14hrs for men, and about 15.5hrs for women.

Fast hiking in that terrain would be 4mph which translates to 25hrs minimum.

The world's best ultra runners can maintain 6+mph average in insane terrain.

[throwup238]

> The record for the Western States 100, which has nearly 19,000' of elevation gain, is just over 14hrs for men, and about 15.5hrs for women.

Tor des Géants (78,700' over 205 mi) men's record is 66:44 at just over 3 mph and that doesn't touch the Barkley marathon with 60,000' gain and under 2mph, though that's more to do with the rough terrain than elevation.

190' per mile isn't that much, especially since the Western 100 ends 5,000' lower than it starts.

[alexey-salmin]

Try walking up a rocky mountain pass and measure your horizontal speed.

3mph at Tor des Géants means running at every runnable segment.

[PaulDavisThe1st]

There certainly are "ultra" routes that essentially require just speed hiking. But the majority of 100+ mile ultras are not like this, and allow capable runners of moving much faster than "speed hiking" pace.

[throwup238]

OP said "Ultra events with 100+ Miles and tons of elevation gain" (emphasis mine).

"Tons" is subjective, but their statement is objectively true for a bunch of ultra marathons - Tor des Géants and Barkley were just the ones of the top of my head. He is not "totally incorrect" as you said.

[rqtwteye]

4mph per hour hiking is pretty fast. I can do maybe 3.5 without starting to jog.

[Melatonic]

Very true. First thing I thought when I read this - how much weight are we carrying? What are the water requirements?

Then again the opposite example (lets say a super hot desert with intense sun - but you can wear a shaded hat or something) might result in the opposite - your feet might still be more tired because walking is slower (and more time on them) but the environment is a huge factor.

[hot_gril]

I'm no athlete, just get around town on foot a lot. Even on sidewalks with no baggage, running at a medium pace with a springy step seems less tiring.

If I'm wrong about that, at least it's obviously easier to run downhill. When walking, it can even take more effort vs flat. But when running, by definition both feet leave the ground at some points, so you have less friction and can let gravity do its thing.

[scns]

Running downhill is very bad for your knees.

[Zacharias030]

I know from personal experience that it is tiring for the knees.

What makes you think that it is „bad“?

[rqtwteye]

That's my experience too. When I hike in the mountains there are places where I can run for a while without getting tired and gain a lot of time. Usually it's the slightly downhill sections. Wouldn't want to fall there though.