Thanks to the several readers who have pointed out this recent article in SEED Magazine which once again dredges up the tired argument that humans evolved to be long-distance runners. Most of you know by now that I totally disagree with that theory. I say humans evolved to be excellent slow movers (walk, jog, migrate, forage, crawl, scramble, etc) burning mostly fat. We also developed into pretty decent short sprinters, but we did NOT evolve to run long distances. Sure, early humans were all-around fit enough and capable of the occasional long easy jaunt after an animal, but to think that natural selection redesigned our simian shapes to run the Boston Marathon is, in my opinion, ludicrous.
We’ve hashed this out a bunch in the past when a Men’s Health magazine article a few years ago quoted Dr. Daniel Lieberman, a leading proponent of the “ER” (endurance running) hypothesis as suggesting that early humans would run an animal to death by chasing it for for 5 or 10 miles until it died of heat stroke. They call it persistence hunting. I find the idea – that this behavior led to some specialized human evolution as distance runners – to be preposterous on several levels. First, much of the fossil record suggests early humans were scavengers and lived pretty well off road kill until they started employing weapons a few hundred thousand years ago. No real need to run long distances when you can walk, hide, climb, sprint and crawl to scavenge. Secondly, it’s one thing to track and stalk an animal (using your superior intelligence) with walking, occasional jogging and a few sprints here and there. That’s a primarily fat-burning pursuit and it’s probably how our ancestors actually hunted. But once you have to shift into glucose/glycogen mode to run aggressively for long distances, it’s a whole different ballgame and you encounter a big problem. Run out of glycogen chasing a beast too long in the heat and you become exhausted yourself. If you are lucky enough to bag the beast, at least you get to eat now (albeit mostly protein and fats which won’t completely restore your glycogen reserves). But fail in your mission and your sorry, fatigued, glycogen-depleted butt is now vulnerable to becoming some other beast’s dinner. ER makes no sense to me from an evolutionary perspective.
So now comes Lieberman again in this latest study in The Journal of Experimental Biology (abstract) that compared the mechanical forces in the feet and the metabolic costs of generating these forces to arrive at the following conclusion: “The increased mechanical cost associated with long toes in running suggests that modern human forefoot proportions might have been selected for in the context of the evolution of endurance running.” He basically argues that humans evolved to have shorter toes than our simian relatives because longer-toed relatives were selected out. That same theory would therefore imply that longer-toed ancestors died off at a greater rate as a result of needing an average of a tiny bit more fuel to run after prey for long distances? Hmmm. I’m not buying it and I’m surprised that the JEB bought it. Since the study concluded that there is no difference in cost between long toes and short toes when walking, I could even use that data to shore up my theory that we evolved to be efficient walkers who could sprint when required and who were fit enough to run after the occasional mastodon if it made sense. And then there’s this: If men did most of the hunting, how is it that women are better suited to ultra running than men (compared to shorter running events) and a modern female like Ann Trason can beat most men today straight up in every ultra running event she enters? (Granted, she could be an outlier.)
Of course, the ER proponents typically cite the Tarahumara as current examples of the human genetic propensity to run long distances. This tribe of indigenous Mexican people are known for their prowess in running great distances (often 50-80 miles in a day) and for their participation in occasional persistence hunting, where they literally chase down deer until it is so exhausted they can walk up to it and kill it. But other scientists suggest that the Tarahumara’s endurance is based more on a cultural adaptation (no cars, no phones, no mail service), training, diet and conditioning than it is on heredity. Some 80% of their diet is complex carbs from grains and beans. That goes back to my primary argument as to why we did NOT evolve to be distance runners. Until we had a ready source of reliable high-carb fuel, made available through agriculture, any sort of regular distance running (chronic cardio) was a natural selection killer. Eating grains every day at every meal certainly replenishes the glycogen stores, so you can go out and do it again tomorrow. But why?
Most anthropologists would agree we didn’t evolve to swim. We learned how to make our way through water without drowning and we do it pretty effectively for a land mammal. That doesn’t make it natural or adaptive. Similarly, I say we learned to run marathons when we had the luxury of unlimited carbohydrates. That doesn’t make it adaptive or natural.
One final point I’ll address is the claim that the large size of the human gluteus maximus is further evidence in favor of the ER theory. I would argue that the move to bipedalism makes the default resting position the squat (as I touched on in this video) and that the range of motion and strength required for this position necessitates strong and well-developed gluteus maximus and hamstring muscles. Look no further than your local gym to see how people train these muscles – squats, lunges, deadlifts etc.