Born to Run?

As I pondered (weak and weary) on my morning run not dreary I was struck by an apparent contradiction. I’ve read that humans evolved to run; that we have all sorts of adaptations that are needed for running but not for walking (or crawling or lying in hammocks).¹ On the other hand I read of a recent study on running injuries which did not use experienced runners because they had too many preexisting injuries.² So… if we have adapted to run well since the days of Homo erectus why do we expect runners to be injured? If you’re well adapted to something it shouldn’t injure you. Presumably it didn’t 20,000 years ago…

How is the modern runner different from those of the Mesolithic?

Well what could explain it?

  • Changes in external conditions
    • shoes
    • pavement
    • age
  • Changes in training
    • Wearing shoes from birth somehow trains us to run poorly
    • Other aspects of the modern life-style are not conducive to running
  • Changes in us
    • People in the US are particularly injury prone due to outbreeding depression
    • Modern humans do not need to run so there is no selection pressure to retain running adaptations, and therefore these have degenerated.

A lot has been written about how barefoot running is best and shoes cause running problems — either directly or indirectly by leading to bad running style. But from what I have seen there are few studies which actually support these claims³.

Most modern runners either run laps around a track, or run on concrete or asphalt roads. My personal belief is that the sharp turns on the track and the hard surface of the road are hard on my legs. It would be interesting to find a study which compared injuries among trail/road/track runners to see if there were any significance differences.

In SB there were no old runners in our races during the 50s. Perhaps the current injury prone nature of the sport has to do with the fact that now there are so many older people running. In 2012 there were more runners over 35 than between 18 and 35 in Santa Barbara races. But although age may be a contributing factor it cannot alone account for the injury-prone nature of the sport.

The US is called a melting pot, it is a nation of immigrants. This produces the possibility of “outbreeding depression”, where the offspring of two dissimilar parents are less fit than either of their parents. If some genes that affect the development of the tibia come from Ireland, but those which affect the development of the fibula come from Poland, while the kneecap genes come from China… well, maybe the leg just doesn’t work as well if all the genes were coadapted. It would be interesting to see a study that compared running injuries in the US or Canada to Japan or Finland.

I’m colorblind. About 10% of the males in the US are. Colorblind monkeys die. Sometime in human evolution we lost the selection pressure against colorblindness. Perhaps when we started planting gardens? Perhaps something similar happened to running? It would be interesting to compare running injuries in bands of hunter-gatherers (or recent hunter-gatherers) to modern runners.

3 Responses to “Born to Run?”

  1. Jim K Says:

    My belief is that the extraordinary regularity of the surfaces on which we run, and the “rigidity” of our repeating patterns (running at the same time every day, and for the same amount of time, and often along the same routes) — neither of which was ever selected for — are a strong influence.

  2. Jim K Says:

    I also apparently believe in recursive sentence structure.

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