Tuesday, April 9, 2013

The most expensive running shoes for a professional Marathoner

Believe it or not, while you or I may be able to acquire these shoes for a little over €100, a professional Marathon runner would have to be prepared to pay thousands of euros to compete in them. This is because they would have to renounce the juicy sponsorship deals that the likes of Nike and Adidas pay them to cross the finish line while showing off their products.

Look at the size of those things
For example, Patrick Macau, the current Marathon World Record holder runs in Adidas Adizero Adios shoes which promise to be "feather light" at only 210 grammes each. The Vibram SeeYas, on the other hand, only weigh 136 grammes. There are, of course, other things to take into account than pure weight but I personally don't count among those their soft, energy absorbing soles. While it is true that elite Marathon runners have to tolerate both much larger volumes of training than I could imagine doing as well as much higher velocities which translate into significantly higher ground forces, they are also in correspondingly better physical condition. They also weigh much less, have much better natural elasticity but (probably) have less actual brute force leg strength than I do.

There seems to me be an extended myth that the cushioning of running shoes somehow returns energy. What I find bizarre is that this claim is made at the same time as saying that they help absorb energy and therefore prevent injury. One day if I find myself with a lot of spare time I'll try to work out the physics of it but my intuition tells me that the key here is elasticity: how much energy is returned and, most importantly, how quickly. Think about dropping a cricket ball on a hard floor, how quickly and high it bounces back. Then drop a tennis ball. Now a chicken sandwich. The elastic response of the sole somehow has to have packed into that relatively small space the same or better efficiency as the Achilles tendon, not only in terms of energy return but also in terms of rate of energy return. In a recent study of the physiology of elite Kenyan runners compared to non-athletic Caucasians, a significant difference in terms of elasticity of the Achilles tendon was noted, evidenced by higher rebound heights and shorter contact times.

In terms of unnecessary extra work done, the Adidas shoes - which, it must be said, are probably amongst the best of a bad bunch - require approximately 42,196 x 0.825 * (0.210-0.136) = 2,576 Nm which is equivalent to Patrick Macau having to climb an extra 46 metres vertically or about 19 flights of stairs after crossing the finish line of the Marathon. According to Ed Frederick - who, ironically enough, worked in the research department at Nike in the 80s - shaving 110 grammes off the weight of each shoe would lead to a Marathon time between 2 and a half and 3 minutes faster. If true, that would put Patrick Macau with his Marathon PB of 2:03:38 tantalisingly close to breaking the 2 hour barrier.

I look forward to the day when Marathons are run in true minimalist running shoes or, as Bikila did in the Olympic Marathon in Rome, barefoot. (For those of you who don't know the backstory, Abebe Bikila was a last minute substitute for the 1960 games for the injured Wami Biratu. Even back then the runners had to wear shoes made by the sponsors - in this case, Adidas - but they didn't have any in Bikila's size, so he decided instead to run the Marathon barefoot rather than in an ill-fitting pair. I find it quite ironic that it was because of a running shoe manufacturer and not in spite of one that the World got to see that it was possible to run a Marathon barefoot and win in record time.)

Maybe we should launch a Kickstarter project to sponsor the top Marathon runners in the World to wear whatever shoes (or not) they want to run in.

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