Probably the ones I was born with.
For the most part running is easy. I know some of you may feel otherwise but go with me for a moment here. Lately I've been online looking for some new running shoes. As I looked at various shoes, checking tread, last shape and the position of flex grooves, it occurred to me why I was so comfortable picking a shoe without having tried it on. I also realized I am in a unique position to comment on the subject of picking a shoe because for almost 9 years I worked selling running shoes at RunTex here in Austin, Texas. During that time I got to observe a lot of feet, shoes, and people running.
By nature I've always been an observant person and typically I've been known to notice things that others might not. As I was looking at shoes online, something that had occurred to me during my time at the store came back to me. While I worked at the store after dealing with perhaps thousands of runners of all ages and abilities, a certain pattern emerged. Over time I started noticing the runners who ran only in racing flats, or the most minimal shoes for all of their runs, be they long or short, fast or slow, were typically the runners who were injured the least. Because of this, even though I probably wasn't consciously aware of it at the time, I did more of my runs during triathlon season in my racing flats as well, only running in trainers during the winter when I tended to run longer and slower.
This past Christmas, I was given a new book on running by Matt Fitgerald, Brain Training for Runners. In it he says,
"...But what is certain is that shoes make most of us run unnaturally..."
Much of what he concludes about running shoes and their effect on running mechanics comes from research he has done in his career as a runner and fitness writer/expert. I came to many of the same conclusions from observations made while working at RunTex and, oddly, by closely following the NBA via fantasy basketball for a number of years. One of the intriguing features of fantasy basketball at the time was the inclusion for many years of the Injured Reserve Listings. Because of this I took note of the steady increase in the number of cases of Plantar Fasciitis suffered by NBA players. While growing up, and playing in elementary school, high school and college, I never came across one athlete with the condition. So I suspect the problem is twofold. One issue is the society's movement toward a more sedentary lifestyle as a whole where walking was less and less common. The other problem is the shoes we wear. Between the endorsements athletes get for wearing a particular shoe versus a shoe that is made specifically to move in the same manner as their feet, and the industry's reliance on more and more shoe "gimmicks" to sell their products, many, many feet have suffered. Even those of highly conditioned athletes.
For a more detailed explanation and description of how deep the rabbit hole goes check out this April 25, 2009 article from the UK, The painful truth about trainers: Are running shoes a waste of money? Also if you haven't seen this article about how humans evolved as runners which was a huge factor in determining our survival as a species check out Born to Run from a 2006 issue of Discover Magazine.
After reading Matt's book, the Discover Magazine article, and the UK article, and incorporating my own observations and experience, my thoughts on selecting my next running shoe boils down to keeping these 5 things in mind as I buy:
1) The shoe should fit snugly. Common wisdom is for a thumbs width at the end due to the swelling of the foot during long distances. The reason typically sighted for this was the loss of toenails. But the length the shoe can be shorter if the height in the toebox is adequate and/or the materials the shoe is made of are selected carefully. The most notable observation on the recommended additional length is that it tends to destroy the integrity between your foot and the shoe. What I mean by this is extra space tends to be the cause of slippage in the heel, improper placement of the arch and thus arch support, and fore foot slippage where the whole foot tends to slide down to the front of the shoe.
2) The shoe should resemble the foot it is going on. There is a place for shoe shaping in this world, but the shapes of the feet and the shoe should resemble one another. If the last (or mold around which the shoe is designed) is straight anatomically then the foot going into it should be as well. That being said what makes a straight foot is not just the absence of an arch but the relationship between the heel and the big toe and the angle of variance. More often running shoes are sold based on what they prevent the foot from "doing" (many times based on a set of assumptions relating to the presence or absence of an arch) and not how the foot actually works. A shoe shaped like the foot it is on is one that is more likely to "move" in conjunction with the foot it is on. This is really what you want.
3) The foot should be considered in relation to the rest of the body in any gait analysis, and by association, so should the shoe. Basically, "the hip bone is connected to the thigh bone and the thigh bone is connected to the.." You get the picture. Your body is a collection of lines and angles and these are all acted upon by the forces movement places on them. It is absurd to think that "pronation" or "supination" are defined by a single articulation of the foot. Nor can they be addressed by a shoe without considering that shoes affect on the body structure as a whole. Nature has given us these marvelously complex yet functional things called feet and unfortunately most of the shoes we wear do not allow them to function as intended. By comparison, even the most technologically advanced shoe is woefully inferior. Think the counting blocks you used in kindergarten versus the computers used to trade securities on the global monetary exchanges or a Cray supercomputer. Try looking shoes that allow your feet to work as they were designed which is in conjunction with the rest of your body and stay away from the ones that promise keep you from doing something.
4) Price does not always follow function. Unfortunately the most expensive shoes are typically the most rigid and the least "foot-like." Basically, the more companies seem to put into a shoe the less it acts like one. Shoes like the top line Nike Shox which can retail for around $115.00 or the Adidas 1 at $250.00 (the one with the microprocessor that is supposed to "think" for you) aren't really designed to work in conjunction with your foot. Look at it this way. Most top end running shoes provide most of their cushioning/technology in the heel in the form of extra cushioning, stabilizer bands, or heel counters. Try this. Run in the shoes you think you want. Then run barefoot. Basically one thing will become pretty clear as soon as you run barefoot. You won't be running heel to toe. You can't. At least you can't for very long. Your foot isn't designed for you to run that way at all. So all the technology most companies put into the heel of their shoes is being wasted. Mostly it just amounts to added weight making the shoe about as useful as a vintage high heel pump (I'm being a bit sarcastic, but you get the idea). So if you can't run the same way in the shoe as you would run barefoot, keep looking until you find a shoe that allows you to.
5) My Tai Chi Sifu said "American shoes make feet stupid." I didn't know what he meant until I had spent a lot of time walking and running barefoot. From the experience I learned the foot is an incredibly complex sensing organ designed to "find" the proper alignment on contact, going from soft and flexible to rigid in stable in an instant. Healthy, intelligent feet always strike neutral from my experience and observation. But by buying into the massive amount of marketing hype and selecting shoes that actually impair our feet's sensing ability, we have effectively blindfolded our feet and tied them behind our "backs." It is no wonder we see so many injured runners. Ironically we are more prone to believe our injuries are the result of our own poor biomechanics or ambitious training and racing goals thanks to effective marketing of shoe companies than the very shoes we are spending all this money on. Instead of throwing money at the problem, we should spend more time cultivating actual foot awareness, strength and intelligence.