Is it true that there have been human runners who have outran horses (over the course of a long period of time)? I have even heard people say that some runners can beat riders who change their horses repeatedly. But I have never seen evidence for this.
Have you heard of any cases that show a human runner to be able to beat a horse, or even a rider who changes horses?
I looked into this some more, and I'll share my findings here.
100 Miles Record
In the FEI Endurance Riding Competition senior level, horses travel about 100 miles in one day. The world record for a human going 100 miles was recently achieved by Zach Bitter, who went the distance over a track field in 11:47:21.
The world record for 100 miles by a horse, appears to be set by Yousuf Ahmad Al Beloushi with 11-year-old grey gelding Jayhal Shazal, at 5:45:44. The previous record holder completed the course at 6:21:12, which is approximately the time of several others. I'm not aware of the conditions the race took place, but it may well have been across a desert as many of the FEI Endurance Races are.
Man vs Horse
I have looked into the man vs. horse marathon. I compiled a spreadsheet organized from fastest to slowest time: https://docs.zoho.com/sheet/published.do?rid=20ske6e0ff973f37949dc925b043e33986264
Out of the 34 champion horses and champion humans, the top 24 horses were faster than 32 of the humans. The fastest horse was almost 40 minutes ahead of the fastest human.
Weather has been considered the main factor in the performance of the horses. I'm not sure if the evidences demonstrates that. Llinos Mair Jones on Sly Dai performed the race in 2:07:04 in "Hot" weather, which is still better than 26 of the 34 human champions' times. The weather likely does affect the horses' performance, but it seems to depend largely on the individual dedication and ability of horse and rider.
Having seen some events, I understand the involved horses to mostly be older ones with the riders not being interested in pressing them for victory. Comparing this event to the FEI races, which can go up to 100 miles instead of 22, the horse and rider seemed more reserved (I maybe mistaken). This would explain the gap of 1:11 between the slowest horse (Geoffrey Allen on Lucy (2:31:26)) and the fastest (William Jones on Solitaire (1:20)).
Marathon
Philippides of Marathon is probably the most famous example of a runner as a messenger, instead of a horse (as well as the famous charge in the battle). It is quite possible he would've been a much better candidate for running the message than any horse the Greeks could have supplied (I would have to leave this to an expert of the field). Philippides is estimated to have run approximately 26 miles in approximately 3 hours, which implies an overall speed of 8.667 MPH, over unknown terrain (which may've lengthened the distance and made the going hard). Philippides also famously died after his run.
While impressive, this famous act does not seem to compete with the feats we know horses can perform, unless we assume the terrain difficulties would greatly impair the horses. It's possible there is a more impressive example of running in history which we are neglecting.
Multiple Day Marathons
Over 100 miles, it seems a horse will win. But what about a longer distance that takes days, or even weeks to cross? There have even been no-sleep marathons where runners keep walking for long periods of time. Could a longer distance and period of time allow a human runner to beat a horse?
Yiannis Kouros ran 473.495 km in a 48 hour period, that's close to 300 miles. A similar feat was accomplished in the 1893 ride to Chicago, where John Berry of Chadron travelled the last 150 miles within a 24 hour period. Notably, riders were allowed two or more horses in that race, but the race did total something close to 1,000 miles over 13 days.
So, in the end? Hard to determine. We'd need a more similar comparison than I can find.
Conclusion
While humans can and have outrun some horses, particularly over distance, it seems that a well picked and trained horse with a good rider consistently wins over human runners in a one-day run of 100 miles or less. It is uncertain if this holds true over multiple day marathons due to lack of a proper comparison, though both contenders perform strongly.
The one thing that humans are physiologically superior to over any other creature on the planet is long distance running. Sweating, rather than panting, loss of fur, organ and skeletal changes to support distance running, etc. Our bodies are essentially what happens when Nature takes a primate and completely redesigns it for persistence hunting. Wolves and dogs (also persistence hunters) can compete with us, but likely only in colder areas where our theromoregulation advantages aren't as great.
However, horses beat us over medium-longish distances (if it isn't too hot), so a sensible human with a pre-arranged route will go even faster by planting fresh horses at intervals such that one horse never has to go further than that medium distance.
Note: Although IMHO most of the answers there have issues, there is a related question on skeptics
The most famous example is probably Philippides in the Battle of Marathon. Humans can run longer distances than horses, and is a key hunting tactic employed by hunter and gatherer societies when they are chasing four-legged prey. Knowing this, we have the reason why Philippides was sent on foot instead of on a horse.
It staggers belief that the Athenians wouldn't have used horse messengers in the Darian invasion, for several reasons:
1) The apparently apocryphal nature of the story about the runners given a lack of clear historical anecdote, 2) The hard to believe situation in which rational Athenians faced with an invasion of vengeful Persians a few miles away would have sent a human runner to travel 150 (or three hundred miles??) to Sparta and relied on this guy for their possible very survival--doesn't sound likely. 3) The Greeks had and used horses for a long time. Their artwork and their literature, such as the Iliad, (the Trojan Horse?) are shot through with horse references.
I am struck, as a formally educated historian and art historian, by how often historical questions of this sort forget the role of good old common sense (or 'horse-sense'?) in our distant ancestors and their ability to act in a way that we moderns would consider rational. The Greeks were not idiots.
Also, is it really unreasonable to suppose that there were established trading routes/highways/pathways between Sparta and Athens that could accomodate horsemen? The messengers would not have been trammeling raw wilderness. Established routes of travel and communication would have been established in the area for perhaps millennia in lower Greece prior to the invasion. Certainly of little difficulty for experienced Greek horsemen. And everybody knew the way to Sparta. There may even been an established posting system (!) already in place for the messenger (or traveling salesmen or merchants) to avail themselves of in their journeys..
