Marathoners endure a lot to get to the finish line‚ but they are doing what comes naturally. ZOE CORMIER explains how humans evolved to be able to race great distances
Every year‚ thousands upon thousands of people take part in one of humanity’s oldest and toughest athletic competitions: the marathon.
Not all of those who try to run the 42 kilometres and 195 metres succeed. Many who do will stagger — sweating‚ wheezing and aching — across the finish line‚ and will spend the next few days utterly fatigued.
“You are completely depleted‚ there’s just nothing left at the end‚” says Tania Jones‚ who will be among 5‚000 people competing in the ING Ottawa Marathon tomorrow. Your buttock and leg muscles are so worn out by the end‚ she says‚ “some people find that they can’t even go down stairs — they actually have to walk backwards.”
Ms. Jones‚ who was the top female Canadian when she last raced in the Ottawa marathon in 2002‚ runs about 150 kilometres a week in preparation for this gruelling event.
Although the thought of running five kilometres — let alone 42 — sounds like utter misery to most of us who spend more time on the couch than on our feet‚ “anybody could make it through the marathon‚” says running coach Ken Parker‚ one of the founders of the Ottawa marathon. “You just need a bit of willpower.”
He may be right. Research suggests that long–distance running is “fundamental to being human‚” says Daniel Lieberman‚ a professor of anthropology at Harvard University.
“Marathon runners are not odd — they are doing something that is biologically very natural‚” he says.
“Humans are pretty pathetic sprinters‚” he says. Pit us against any animal‚ even a squirrel‚ and we would lose miserably. The best human sprinters in the world can barely top 10 metres a second for a few seconds‚ while horses‚ antelope‚ deer and wild dogs can run faster than 25 metres per second for several minutes.
“But humans are exceptional long–distance runners‚” Dr. Lieberman says. “We can outrun most creatures on the planet‚ and can even give horses a good run for their money.”
Just ask Englishman Huw Lobb. He won £25‚000 in 2004 when he won a 35–kilometre race against 40 horses (and 500 people)‚ becoming the first person to ever win the “man–versus–horse” event held annually since 1980 in Llanwrtyd Wells in southern Wales. The competition supposedly originated in an argument between an innkeeper and a fox hunter over who could win a race: man or horse (the innkeeper was betting on man).
Mr. Lobb’s victory was no fluke‚ Dr. Lieberman says. He‚ along with University of Utah biologist Dennis Bramble‚ think that long–distance running was instrumental in the evolution of modern humans. Their work‚ published in the journal Nature in 2004‚ is a radical departure from traditional theories that try to account for the dominance of humans on this planet.
“The basic thinking about humans has always been that we are the nerds‚ the wimps‚ of the animal world. We have big brains‚ and so the basic story of our evolution was that we somehow outsmarted other creatures‚” Dr. Lieberman says. “But actually we are incredible athletes‚ and this athleticism is important in our evolution.”
Dr. Bramble and Dr. Lieberman are certainly not the first scientists to focus on human locomotion. Countless scientists have scrutinized the evolution of walking‚ made famous in those well–known illustrations of our progression from knuckle–walking apes into striding humans.
“It’s not that walking isn’t important‚ but it doesn’t distinguish humans from everybody else‚” Dr. Bramble says.
Chimps can walk on two legs (albeit not very gracefully). Our ancestors‚ such as Austrolapithecus afarensis (the famous “Lucy” is an example)‚ walked habitually at least 4.4 million years ago.
What ultimately set us apart from the rest of the primates was endurance running. We are the only ones — in fact‚ we are among the few animals on the planet — who run long distances (notable others include hyenas‚ wild dogs‚ wildebeest and horses).
Endurance running emerged about two million years ago among Homo erectus. This early human had only a slightly bigger brain than Austrolapithecus‚ but he could run. This‚ Dr. Bramble and Dr. Lieberman argue‚ was a key step in our evolution from mere walking apes into big–brained‚ tool–making‚ abstract–thinking Homo sapiens.
By running long distances‚ they argue‚ we would have been able to obtain far more meat than other primates. And eating energy–rich meat‚ instead of leaves and fruit‚ allowed us to grow our distinctive big brains.
Indeed‚ some modern hunter–gatherers chase down prey to exhaustion‚ often pursuing animals for one or two days before tiring them out. Anthropologists have documented this behaviour among African Kung San (“bush men”) hunting gazelle‚ wildebeest and zebra. Tarahumara Indians in Mexico and Australian Aborigines have been known to do the same with antelope and kangaroos.
However‚ Dr. Lieberman and Dr. Bramble think that it is far more likely that our running abilities stem from a less impressive behaviour: scavenging. Swift–footed humans might have been able to reach the site of a kill some distance off — signalled by vultures circling overhead — before other more dangerous predators got there.
For whatever reason‚ we were born to run. Dr. Bramble and Dr. Lieberman point to a number of traits‚ which are not found in other primates‚ as evidence that ancient humans evolved to be long–distance runners. These anatomical anomalies are not needed for walking‚ but are crucial for running.
We have long legs for a primate‚ which give us bigger strides. We have a number of tendons in our legs‚ most notably the Achilles‚ that act like springs to give us extra leverage. Long–distance runners can get an incredibly painful injury in the Achilles tendon — tendonitis‚ a condition from which Mr. Jones herself has suffered.
Our toes are small‚ and we have an arch in our foot‚ which helps us to push off. Plantar fasciitis (when the connective tissue becomes inflamed) is a common ailment in long–distance runners.
Our joints in the ankles and knees are wider and sturdier than in other primates‚ which helps to absorb shock and prevent damage to the skeleton when our feet hit the ground; after running a marathon‚ most people report sore knees and ankles.
We have massive gluteal muscles (they are the largest in the body)‚ which stabilize our posture while running; rarely do any of us feel pain in our buttocks after a walk‚ but Ms. Jones can certainly attest that her gluts are sore and exhausted after a marathon.
Our upper bodies are adapted to running as well. Our arms are smaller and lighter than in apes — useful in running because they are easier to swing for counterbalance. Our shoulders are not as strongly connected to our heads and necks with muscles‚ which makes it difficult for us to swing from trees‚ but easier to balance our heads while running.
And we easily rid ourselves of excess body heat‚ which builds up during running. We lack fur‚ we have a huge number of sweat glands (we sweat more than any other mammal)‚ and we can breathe through our mouths — something apes don’t normally do. These ways of getting rid of heat are precisely why hunter–gatherers can tackle larger‚ stronger prey‚ which overheat quickly and will collapse from exhaustion before their human pursuers tire.
And there’s another curious aspect of our running behaviour that could be adaptive: the “runner’s high.”
“It’s just marvellous‚” Ottawa running trainer Rick Hellard says. “You feel pretty much invincible.”
This sensation‚ a result of the brain releasing endorphins‚ could be an adaptation that encourages us to run‚ much as sexual pleasure and orgasms are thought by some to have evolved as “reward incentives” that encourage us to breed.
Although Ms. Jones would not describe running as euphoric‚ “there is a sense of freedom‚ having that ability to power yourself from one place to another just with your own two feet‚” she says. “There’s a real simplicity and pleasure to it‚ which is really why I think the sport of running is such an amazing sport — all you need is a pair of shoes.”
And we may actually be better off without shoes. Ethiopia’s Abebe Bikila set a world record in the marathon at the Olympics in Rome in 1960 without shoes. And the Tarahumara Indians run 100–kilometre races (almost 2½ times as long as an Olympic marathon) barefoot‚ or with just a thin layer of tire rubber strapped to their feet.
There are a number of people who believe it is better for our feet and our posture — in fact our entire bodies — to walk about as we were meant to: barefoot.
Barefooters‚ as they are known‚ “are on to something‚” Dr. Lieberman says. “People who run barefoot‚ and who start doing so when they are young‚ suffer from fewer injuries and have much fewer problems than other runners.”
He has tested barefoot runners in his lab‚ and he says the natural arch of the human foot does a better job of providing support than running shoes do.
However‚ given that most of us live in dirty cities where we wouldn’t want our feet coming in contact with broken glass‚ dog doo‚ ice and other nasties covering our streets‚ he suggests that we try wearing shoes with minimal support in the soles‚ such as the Nike Free.
Now‚ both Dr. Lieberman and Dr. Bramble are interested in how modern life and our many gadgets — from shoes to satellite dishes — have helped to turn us from a race of super–athletes into couch potatoes. We evolved to run as part of our daily lives‚ and yet today only 10 per cent of us jog‚ and obesity runs rampant.
“The human body was strongly selected for high levels of activity‚” Dr. Bramble says‚ “and we have every reason to believe that it needs that to be healthy.”