Along my path of "foot discovery" I have built up a fairly substantial collection of shoes that has certainly not gone unnoticed by my wife. I have very big feet (EUR 48 in running shoes / cycle shoes) which limits my options severely and, in many cases, means I have to buy them from mail order abroad. Apart from the general prejudice that big footed runners must be heavy and therefore need oodles of cushioning, it seems like there are the same protectionist rules governing the sale of shoes that there are for DVDs, CDs, eBooks and video games: I am in Zone 2 (Europe) and most of the shoes I like are only made for Zone 1 (USA) consumers. This is, of course, where ebay comes in.
Things to look for in minimal shoes:
1) Low profile. The sole should be thin so your foot can better feel and anticpate the ground and thus help you land with less impact force and adapt to any uneven terrain.
2) Zero heel to toe differential. Most trainers pitch you forward by raising the heel because you need more cushioning on the heel if you heel strike. Pitching you forward encourages you to heel strike so it is a chicken and egg situation. Better to land on the midfoot / forefoot and do away with the heel counter. By the way, if you are a so-called "over pronator" (what a great marketing invention) then you'll notice that this goes away if you change your landing. This is because the roll of the foot is designed to help absorb (and release) the impact forces with respect to a landing close to your centre of gravity - if you land any further forward the foot is caught in a different orientation. Pronating is not a disorder.
3) Flexibility. Most shoes are like mini-prisons for your feet. Your feet become weaker and more dependent on the support of shoes. A more flexible shoe allows your foot to move as it sees fit. If your foot is strong enough then - perhaps paradoxically for some - the more flexible the shoe, the less chance you have of spraining your ankle for example. Imagine you ran over uneven terrain in a pair of clogs - if you stepped badly then all the force of the torsion would be channeled through the few muscles that were not splinted, dramatically increasing the chance of a sprain.
4) No toe spring. Many shoes curl up at the front so that you can roll off the ground - this is called a "toe spring". If the shoe is rigid then this is necessary otherwise your toes would "nose dive" into the ground. However the euphemistically named "toe spring" actually disables the natural toe spring of your foot.
5) Light. Your foot acts like a pendulum as you run. This is one of the reasons why, the faster you run, the more you tuck your foot into your bum: you shorten the length of the pendulum and it swings more rapidly. However, if you add more weight to the end of the pendulum, it swings more slowly. The energetic cost of a small weight on your foot is much greater than carrying this weight (around your stomach for example). If the shoe meets all the other requirements, its going to be relatively light anyway.
WARNING: Changing your running gait or adapting to more minimal running shoes is something that should be done - if at all - very gradually over at least 6 months.
Misuno Wave Universe III (RIP)
Nike Lunar Racer (RIP)
Terra Plana Evo
These guys are the ones to watch in 2011. Terra Plana are making some seriously stylish shoes which are very flexible, low profile and durable. I've managed to get the kids out of their rock solid shoes with orthotics and they are now wearing various different models of Terra Plana shoes. I picked up a pair of Evos which are virtually indestructable. The soles are so firm that my steps make a satisfying tapping sound, confirming that I am getting sprung back most of what I put in. They are a tad on the heavy side for being a minimal shoe but this is the price you pay for their ruggedness, although perhaps they have gone a bit overboard with the uppers. This one of the problems I have with the shoe: I end up getting blisters on the tops of my toes!! This is because the upper folds back on itself when my foot bends and rubs against my toes. There is a new model, developed in conjunction with POSE Running guru Lee Saxby, that I have yet to get my hands on. It has a more conventional upper. Hopefully it fixes the other problem I have with the shoe and that is that the back of the shoe comes up too far and causes some discomfort by pressing against my Achilles. I still use these shoes for running occassionally and they are my favourites for doing strength exercises in the gym.
Puma Street Kosmos
Saucony Kilkenny XC 3 Flat
These are my second favourite shoes (second to the Kosmos). They are very similar in most repects although they have a tiny bit of differential between the heel and toe. The main difference is that they are slightly harder wearing and have much more grippy soles, so they give much more confidence when running cross country like I do on my way to work. They are also a lot easier to get hold of - I still have to order them by mail from the States but its pretty straightforward and they are usually discounted something silly.
Vibram Five Fingers KSO (Keep Stuff Out)
MBT (Masai Barefoot Technology)
How I laughed when I first saw these. They market themselves as the "anti-shoe" and I thought that an anti-shoe, if anything, should be like the Feelmax - something with a waffer thin sole. These shoes are neither flexible, cheap or low profile and they are certainly not lightweight. What happened is that I got fed up of people asking me if I was injured when they saw me walking around in the Feelmax - when you walk barefoot or in socks, you walk on slightly bended knees and tip-toes. The idea behind the MBT shoes is to accept that we walk differently from how we run and that heel striking is OK as long as you are walking. If you start from this premise then, by making the sole of the shoe curved, you find that your centre of gravity moves much less as you walk than it would in normal heeled shoes (i.e., you bob up and down less). MBT market this as it being similar to walking in sand rather than on hard man made surfaces like concrete and it is true that it is a strangely soothing sensation walking in them. The other effect of the sole is that you have no heel counter to lean back on when you are standing - in fact you are constantly in a state of equilibrium like a weeble (until someone sees you are wearing them and pushes you from behind as a joke, as happens to me every so often). The end result is that you expend less energy walking than you would in normal shoes, and more energy standing - at least at first. But that isn't quite the end of the story, because, by being in constant balance, you naturally adopt - by evolutionary definition - the best possible posture. The problem with a bad posture is that some of your muscles become weaker while others become tighter, leading to muscle pain. So your calf muscles may get more tired than usual at first as you get used to them, but - and this is the surprising thing - it works wonders for posture related back pain and knee pain. The shoes are very expensive but they are extremely well made and I personally believe it is worth steering clear of the cheaper and perhaps slightly more fashionable but less effective imitations. You gets what you pays for. Some of them are ugly as sin but I have finally managed to find a pair of MBT work shoes that look like work shoes, at least from above. Prior to my MBT conversion, I was getting pains in my knee from walking even short distances (I have a torn meniscus) although I could happily run for tens of kilometers without problems. This problem has gone away and my posture has improved to boot. Oh yes, and they make me look about 5cm taller....