Prior to barefoot running, I was somebody that wore shoes the majority of my entire life, and for the past 18 years had been wearing tightly laced athletic shoes during my intensive running career. This resulted in my foot had to go though many (sometimes painful) structural changes as I began practicing barefoot running.
I will detail these changes below; however will first observe that my spouse weren't required to go through many of these structural changes, because she'd spent most of her childhood and much of her life going barefoot or in minimal footwear, and thus her feet were better adapted to barefoot running in the first place. Should you go barefoot often, you might not suffer from the structural changes listed below while you start barefoot running.
1. Barefoot running structural change #1: Spreading from the toes.
My toes were very close together when I began barefoot running, and my outer toes even curled underneath the ones next to them a bit. When i began barefoot running my toes all started to spread out, until today, they are quite separate. I have used "toe spreaders" whilst not out barefoot running at times, to help this beneficial spreading process.
2. Barefoot running structural change #2: Bones becoming unfused in forefoot.
If you have been wearing shoes for a long time, you might find when i did that your metatarsals (small bones inside your forefoot) have actually become bonded or fused together, with cartilage. One method to determine if this has happened would be to try to wiggle or move your toes independently; if you fail to, then your cartilage may have bonded your bones in your forefoot and you'll maintain for a painful "loosening" as you begin barefoot running.
My experience as I began barefoot running was that the insides of my feet were in quite a bit of pain as the cartilage broke apart internally. The easiest method to deal with this is to start barefoot running slowly, so that it doesn't happen too rapidly; also to use ice water foot baths to soak your feet in after running. You may also use Traumeel, a gel with arnica in it, to rub on your feet. However you will also just have to deal with some pain as this happens, I understand of no way to totally cure it. However it goes away as you keep barefoot running and your foot heals.
3. Barefoot running structural change #3: Loosening and flexibility of the toes.
As the toes spread apart, and also the bones in your forefoot become unfused, you will see that your toes are not only seen further apart and looser, but that you could begin to move them independently of 1 another, quite simply barefoot running will help you wiggle your toes.
4. Barefoot running structural change #4: A wider, more muscular foot.
My foot hasn't only be a little wider in front, but also much more muscular. Also, the tendons within my feet accustomed to stand up quite a lot, and now they do not, causing my foot to look smoother and without the sharp ridges that used to show from my tendons being strained.
5. Barefoot Running structural change #5: Wherewithal to Be Comfortable Wearing (Any) Shoes.
This is not a lot a structural change as a result of the structural changes you may experience barefoot running: you may find yourself unable (or unwilling) to put on normal shoes anymore. I've discovered this in my experience the case, and today I only go barefoot or wear Vibram Five Fingers (minimalist shoes with separate compartment for your toes).
The final time I attempted to wear shoes was actually when I visited meet President Clinton in a charity dinner (I didn't think they'd allow my Vibrams) and find the preferred "dress" shoes I could, some Doc Martens. My feet and back were hurting the whole night. So, you might perfectly want to purchase a pair of Vibram Five Fingers if you are barefoot running a lot, and get accustomed to the concept that shoes may be a a part of your past!