Where it all begins
Your foot is made up of 26 bones and articulations that create one functional unit of propulsion. 5 phalanges (toes) in the forefoot, 5 solid bones to create the arch, and the two bones that form the heel and the ankle. The articulations are such that the bones, in one direction, create a strong stable platform, but in another direction seem to be entirely mobile and flexible. Your foot is covered with small muscles, tendons and ligaments, and the bottom is covered with the plantar fascia. This is what, ultimately, provides us with propulsion and balance.With that brief anatomical run down of the foot, let's talk about how that effects us.
Well, consider that our very complex feet were built to work in a certain way, but then culture came around and we went and changed the way our feet work. We cover them in shoes with hard stiff soles that don't let our feet feel around when we walk. We stick firm plastic insoles into our $150 Brooks SuperDynamicStabilityUltraRide running sneakers so that our foot becomes, essentially, one solid piece with no movement or feeling. The best analogy I've heard compares feet in shoes to a hand taped up and put into a 16 ounce boxing glove. You've taken something that is naturally very flexible, mobile and sensitive and covered it up and changed its use. Watch a UFC fight, they use tiny little 4 ounce gloves and don't punch nearly the same way a pro boxer does in his big bulky gloves. So, what happens when we wrap our feet in huge stiff shoes and go for a run? Well, we change our whole gait cycle. Yup, we throw on shoes and we effectively change the movement pattern that evolution decided was the most effective way for us to run and move. Seems like a good idea, yeah?
The gait cycle is divded into two phases: the stance, and the swing. The swing is then broken down into 4 more phases: heel strike to flat foot, foot flat to midstance, midstance through heel-off and heel-off through toe-off. This description is really more applicable to the gait cycle of walking rather than running, since a proper running gait cycle should NOT include a heel strike. Let's take a look at some videos, shall we?
So, these videos are depicting just how different running with shoes on and off can be. You can see the heel strike with the shod foot, and the spike of forces that are sharply sent through the body. In the bare foot, you can see how the runner lands on his forefoot, which applies the pressure through the foot/ankle at a nice even rate. This forefoot strike is what runners should be trying to achieve in their gait. Now, as a disclaimer, I'm not suggesting that simply running with shoes on causes a shitty gait cycle. However, the cushioning of the shoe allows you to have a shitty gait cycle and not notice it. This is very evident when I stand in the window of my gym on Saturday morning and watch people train for the marathon on Beacon Street by having what appear to be moving seizures. Just dysfunctional movement patterns out the wazoo. Also, I'm not suggesting that having someone run barefoot or in minimalist shoes will magically correct their gait; if someone has only a dysfunctional gait cycle ingrained in their body, they will continue to have one when they take their shoes off; some people just run like dogshit. However, if they spend enough time trying to do it correctly while barefoot, their body will compensate in the appropriate manner It's called the SAID principle: Specific Adaptations to Imposed Demands. This means that your body will change when forced to. Running with a heel-strike while barefoot is really uncomfortable, and your body will try to avoid the movement causing the pain.
Ok, so now you don't want to run in your Brooks Moon Shoes, but you can't go barefoot yet. I get it, I don't think being barefoot is necessarily the best idea for a runner. Let's explore your sneaker options. The Nike Free is the most well-known minimal sneaker on the market; everybody and their mother is wearing them nowdays. Why? Because Nike marketed the shit out of them and they look nice. However, within the minimalist world, these shoes don't hold a lot of water. Why? Because they really are NOT that minimal.
On the left we have the latest Nike Run2, and on the right we have the current New Balance Minimus Trail Zero. You can see pretty easily that the heel on the Nike shoe is significantly higher than that on the New Balance. This makes the Nike a very good transitional sneaker for someone getting into the minimalist scene. When someone wears high-heeled shoes for a very long time, they will often experience a plastic deformation of their soft tissues; in this case, the achilles tendon. It becomes short and stiff after years of being in the plantar-flexed position. This will cause discomfort when someone suddenly goes barefoot, since they are essentially walking around with their achilles in a stretched position! By starting off a really flexible shoe like the Free, they can start to adjust to a flatter more neutral sneaker. In my personal opinion, the Nike Free is going to cause as many running related injuries as the traditional running sneakers. Why? That big cushy heel. It still protects you enough that you can run with sub-optimal form without really experiencing any pain or discomfort. The Free is, in no way, a bad sneaker. I own a few pairs and I love them for walking around and working. They are flexible and light and they look really good.
A sneaker like the New Balance Minimus Zero (zero drop from heel to toe, i.e. a perfectly flat shoe) takes a little more work to get into for most people. The number of zero drop shoes available are plentiful: New Balance, Vivobarefoot, Altra, Vibram and Inov-8 all make shoes that have no difference in height between the heel and the toe. Some of these shoes come with a thicker sole than others, but all provide the neutrality that our feet desire.
So, who should be wearing what kind of shoes? Well, in my humble opinion, everyone should be doing something barefoot. Everybody. At the least, I'd like to see all of my clients doing their dynamic warm-ups in un-shod feet. Unfortunately, the gym I work at right now won't allow for that. Beyond that, I'd like everyone to deadlift in bare feet. This is a simple way for us to allow the intrinsic muscles of the feet to experience an external load without moving through the gait cycle. Lunging in bare feet is tough for a LOT of people, so it's not something I really move towards; personally I stick to squats and deadlifts as my main barefoot lifts (both bi-lateral and uni-lateral versions). Who should run in these kinds of shoes? Well, if someone MUST do long-distance running, they should wear whatever is comfortable for them. A good friend of mine runs marathons, owns Free's and runs in fully supportive Adidas sneakers. Why? He has a great stride, great forefoot strike and has no running related pain. He runs beautifully in fully supportive shoes, so why change? Another good friend of mine runs exclusively in Vivobarefoot's and has no running related pain. Again, the similarity here is a beautiful stride. When you run perfectly, you can wear whatever you want on your feet and it won't matter. If you look like a monkey humping a doorknob when you run, you're going to experience pain regardless of what's on your feet.
If you want to try running in minimalist shoes, I would say that's a good idea. Take it slow, though. Start with some Free's. Let your feet adjust to the feeling of a light flexible shoe. Spend some time in those before you try a flatter shoe. Do your warm-ups barefoot, do a few lifts barefoot. And, for the love of God, seek out a good running coach if you look spastic when you run.
This was a helluva long post, thanks for bearing with me. If you learned even a little bit, then I did my job. Go lift something heavy!