Tuesday, October 26, 2010

Born to Run

Christopher McDougall - an amateur runner - asks his doctor perhaps the most frequent question asked by runners - "How come my foot hurts?", and when his doctor tells him that the human body - specially his at 6'4" - is not designed to take the kind of abuse that running exposes it to, Christopher McDougall - the journalist -  sets out in search of answers and insights into running. He ends up telling a fascinating story that involves an ancient tribe of running people, elite ultra runners and other crazy characters in his book - Born to Run.

Anyone who loves running or has a taste for adventure should like this book, not the least because of the ensemble of interesting characters involved in the story. The writing style is clever (even though sometimes straining to be too clever) and the author handles the multiple threads in the story quite dexterously and naturally. It is an engaging read which every now and then wanders tangentially to the interesting subjects like history of running and evolution and morphology of humans as a running species.

However, the fault of the book lies not with what it includes but what it fails to. In his zeal to counter the conventional wisdom, Christopher McDougall cuts some intellectuall corners and fails to provide a balanced perspective while making conclusions based on studies that are still work in progress. At one point he cites a study which shows that since the introduction of running shoes in '70s the Achilles complaints have increased by 10%. Now this statistics in itself doesn't tell anything unless it accompanied by the number of runners involved during two study points. The 10% increase could simply have been due to increase in number of runners. The author doesn't think it worthwhile to clear this important point.

Somewhere else he cites a study that found that the most common factor amongst the injured runner was price of the shoes worn and concludes that the most expensive shoes are the most dangerous. His conclusion might be right - but he might as well be completely wrong. What he shows for as evidence is correlation but what he claims is causation and the two are not interchangeable. Let me try to explain what I mean. Consider a very reasonable scenario where all the runners wearing expensive shoes are richer than the runners wearing inexpensive shoes. Further, consider another reasonable scenario where the rich runners lead a lifestyle that is qualitatively different from their poorer counterparts. Now, it is entirely possible that the injury inducing factor in the study is not the shoe type but the life-style of the runner. (McDougall , himself provides some support for this argument when he advocates coach Vigil's nutrition strategy for olympic marathoners: "Eat as though you are a poor person" suggesting that the life-style does play a role in how you train for running.) A well designed study will therefore try to eliminate such correlations. They control for all other factors except for the one being tested. So, in this case a better designed study - where income level and all other factors amongst the runners were same on an average - would have been necessary to reach the conclusion that McDougall makes.

At another point McDougall cites an interesting study by Professor Lieberman that shows how the impact forces experienced by the runners wearing thick heeled shoes are greater than the those experienced by barefoot runners. The study also shows that the way bare foot runners habitually strikes the ground is qualitatively different from the shod runners. While the study is quite interesting and suggests that wearing thick soled cushioned shoes for long distance running might cause injuries, Prof. Lieberman is quick to point out that no controlled studies have yet been done to conclusively prove these claims. So, while McDougall tells that no study conclusively proves that shoes prevent injuries and pitches for bare foot running, he conveniently chooses not to mention that studies to prove his claim - barefoot running prevent injuries - are absent as well. Again, he might be right about bare foot running but - as the Prof. Lieberman says - the current evidence is totally anecdotal and needs further research.

In conclusion, the good things going for Born to Run are its plot, characters and its love for running. However, I suggest you take the scientific claims in the book with a pinch of salt and consult the original studies for a more balanced understanding.

P.S.  Here are the links to the two interesting studies by Lieberman et al. that were published in scientific journal Nature. Both of these studies are relative easy to follow and understand.
1) Link to Endurance running and the evolution of Homo.
2) Link to Foot strike patterns and collision forces in habitually barefoot versus shod runners.
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2 comments:

Bharath said...

Hey,
Liked your review of the book as it seemed to strike the right balance between what was missed out and what was said right. Thanks for the links to the original studies as well..
Happy blogging.
Cheers,
Bharath.

Sachin Tyagi said...

Thanks Bharath. Glad you like it. :-)