I actually did find and had a quick glance at the article @
hhnngg1 was mentioning before.
here's a quick link if anyone wants to check:
http://www.fas.harvard.edu/~skeleton/pdfs/2004e.pdf
I think this is the part you remember about the 100 miles and the horse (which is in km btw)
Fit human amateurs canregularly run 10km, and longer distances such as marathons(42.2 km) are achieved by tens of thousands of people each year.Such distances are unknown if not impossible for any other primate,but are comparable to those observed in specialized mammaliancursors in open habitats. African hunting dogs travel an average of10 km per day, and wolves and hyenas travel on average 14 and19 km day21, respectively14. This is not to say that humans can
outdistance specialized quadrupeds. Some horse and dog breeds, forexample, can be made to run more than 100 km day2 1 whilecarrying or pulling a human. Such extreme and human-inducedfeats, however, should not detract from the fact that humans canand do run long distances well, despite a primate ancestry.
Here's the section about @
WhyFi and his theory of bipedalism efficiency. (Page 346)
The one category in which humans perform poorly compared tomany quadrupeds is the energetic cost of running. The mass-adjusted COT (Cost of travel) of human running is about 50% higher than a typicalmammal, including other primates12. Compared to the only valuemeasured for a chimpanzee (a 17.5-kg juvenile), human running is25% less costly in absolute terms, but about 10% more costly whenadjusted for body mass29. Interestingly, other endurance cursorssuch as wolves and African hunting dogs also have high mass-adjusted COT relative to the average mammal12.
I am not telling anyone is wrong or right. Since we cannot reanimate the exact conditions of our early ancestors, any study will be incomplete.
Fun reading:
http://en.wikipedia.org/wiki/Man_versus_Horse_Marathon