ARTICLE: Why shoes make you fragile–Part 1 of “Antifragile” exposition

The world's perception of "risk" was shattered by the series of books written by Nassim Taleb, first “Fooled by Randomness”, then “The Black Swan” and finally “Antifragility”. The content has triggered Taleb to be considered among the world’s most important thinkers. His views on risk are informative when we consider the conundrum on the attitude towards running shoes versus bare foot.

Today buying a pair of cushioned running shoes is considered the sensible and safe choice. Similarly, going to see a physiotherapist or doctor is also considered the standard option, the one that we fall back on when we get fearful, anxious and feel out of control. On the other hand, seeing a coach who can teach you how to move well, how to eat correctly, how to manage your stress and to adopt the right lifestyle and habits to match your goals, is seen as "the risky investment". 

Understanding risk

Nassim Taleb had to coin a new term as the title of his latest book "antifragile" because there was no word for this concept anywhere in any language he checked. Fragility essentially describes the properties of something that is hurt more than it gains from different types of volatility - chaos, randomness, disturbances, uncertainty, and stress. Most man-made items are either fragile (coffee cups, shoes, tape). The more disturbances and stress you apply to a shoe, the more damaged it's material becomes. Some objects are robust (diamonds, steel bars) in that they generally are neither harmed nor benefit from stress. Only natural systems at the moment are "antifragile" - and this includes us humans, of course - simply we put we thrive on stress, disturbances and uncertainty (in the right amount) and when subjected to it, come back stronger than before (we benefit from volatility).

Taleb uses a simple decision-making framework for you to decide what actions are worthwhile taking and which are not. Essentially, if the potential harm is low but the potential benefit is high, you have what is called a "convex development" which means that you have "more gain than pain" from an event. A classical example is a flu - not taking any medication may increase symptoms in the short term but you'll come back more resistant to the disease and without having taken the risks associated with all drugs (e.g. if you are the 1 person out of 1.000.000 intolerant to the drug, you could die. A risk you would take for very little benefit). Concave

The green line is an example of “convexity” (short term pain,long-term gain) versus concavity (short term gain, long term pain). I consider modern running shoes, most drugs, orthotics and similar magic bullets in the latter category.

So what about cushioned running shoes, presumably the “safe and sensible” choice:

The risk of running shoes

Let’s consider some facts about running shoes:

  • We know that they alter the runners movement pattern (by removing sensory feedback, introducing softness under the foot of the runner and by shifting their postural alignment)
  • We know that no clear evidence exists that they have any beneficial effects on either performance or injury prevention

The only benefit that we could treat as “reasonably certain” from modern running shoes is that they provide temporary comfort compared to running without them (even this is not true when dealing with a natural runner – but let’s leave that aside for the moment). For shoes in general we know of one benefit that is likely the main driver for the invention of shoes:

  • Protection from the environment (sharp objects, cold etc.)

Also we see this benefit:

  • Unskilful runners are sometimes able to run significant distances that they could not run barefoot *

* This benefit comes with a trade-off – inevitable injury

On the other hand we know that running shoes have these effects:

  • Change the running style of the runner
  • Slows down or eliminates sensory feedback from the feet to the mind thus:
  • Preventing the runner from changing their physical shape to match the forces involved in their running
  • Changes upright posture (in the same way high heels do)
  • Interfere with the function of the foot and semi-permanently alters the foot when worn for long periods or since childhood
  • Squeezes the forefoot together
  • Soften the skin, stops development of natural pads
  • Makes sensory nerves in foot hyper-sensitive
  • Interferes with nerve signals that dictate the degree to which proper bone development should happen in response to exercises

Choosing running shoes are thus a concave decision (the opposite of convex – see below) meaning that you have very little potential gain (quick comfort, heat when it’s cold, short-term ability to run higher volumes than you skill level otherwise allows) mounted against significant risks (deformed feet, chronic injury). This decision in turn makes a shod-runner essentially fragile – as in, they grow weaker from chaos and randomness.

In the early stages of running shod, unskilful runners may see their exercise capacity increase. This benefit comes from a form of “proto-antifragility” called “hormesis”: “when you take a small dose of certain poisons it may provide benefits but at a certain point it becomes lethal – take alcohol, small doses may provide certain benefits (such as enjoyment) and increase resistance to the poison. But high doses are potentially lethal and will reduce the organisms resistance to the poison in the future:

File:Hormesis dose response graph.svg

This is exactly what happens when you run shod. Because of the effects above you may see a quick boost (for instance you can now easily run over a gravel road without feeling anything even with horrendous running technique). For the first period of your running career, the body will try to adapt to the stressors being forced on it (calcifying joints, building more muscles etc.). This “strength” is illusory, however, and only protects the runner to a certain point (the maximum “safe dose”). After this point, incorrect usage of muscle and joint tissue, compromised posture, atrophied feet and other mal-adaptations will have left the runner less resistant to stress than they were before. The runner is now fragile and will be increasingly vulnerable to chaos – especially extreme events.

Technical training  – antifragile?

We know that natural evolution progresses in an antifragile manner: when chaos occurs, the weakest members of a species dies. But this makes the species stronger as a whole (thus species are antifragile – they benefit from harm in the longer term). The individual human is likewise – as long as the stressors are not overwhelming (e.g. “getting hit by a bus”) or chronic (e.g. “constant incorrect loading of a joint”).

So with a running shoe, you have uncertain benefits and very real long-term risks whereas technical training is likely to inflict some short-term pain (tougher to do, less comfortable at first, potential loss of ability to do same “volume” early on) but will provide long-term gains (correct strengthening of the body, no interference with the bodies natural movement patterns etc.).

When examined this way the common wisdom that “bare foot is bunk” (include barefoot technology footwear here) and “cushioned shoes are needed” are undermined. Shoes try to remove randomness but by imposing this fix on a complex system such as a human being, you get similar effects as when you try to bail out banks to protect an ailing economic system – the next time you’re hit by a crash your system is even more fragile than the first time.

On the other hand when you teach yourself a skill, you can indeed temporarily lose something (time, ability to compete) much as when you change a golf-swing. But learning a skill is almost always a long-term gain. So the runner who wishes to make himself “antifragile” learns the skill. The runner who wishes to remain “fragile” or merely try to make himself "robust” will invariably seek out quick fixes. Doping follows the same principle – quick immediate gains but with huge risks of long-term health problems. Unsurprising that it is easy to convince us that shoes are a good idea.

In my next instalment I will look at why traditional strength and conditioning, physiotherapy, medication and generally also represents a “concave” choice – e.g. short-term gain for long-term pain.