I'm sure we've all heard about people who train barefoot. A lot of us have looked at them like they're crazy. Shoes give added support, cushioning, and protection to the foot, right?
Well, is it right? First lets look at some anecdotal evidence:
Shoes are a fairly recent invention, being only several thousands of years old. The Hominini tribe, the earliest ancestors of Homo-sapiens genus, divulged from their Pan genus brethren 6.3 million years ago. The human foot, and all the body's supporting mechanisms for the foot, evolved over millions of years to be fairly good at what it does. We could probably trace the evolution of the human foot even farther back, but lets go from there. Human feet were designed to be walked on. Shoes stop you from walking on them.
You are probably wearing shoes right now. Take them off, and put one on your desk. Look at it. Do you see how the toe is curved upward? This is done so it is even possible to walk in shoes.
When you walk barefoot, you strike with the middle of the heel, rolling forward onto the balls of the feet, and then there is a powerful push-off from the balls of the feet. When running, they were designed to strike in the midfoot, not the heel. Shoes alter your gait - when you walk in shoes, the back of your heel strikes first, and your foot rolls forward, and then you push off your toes which creates a rocking motion. When you run with shoes, it feels "natural" to run heel-to-toe, which causes a jarring shock to your ankles and knees. High heels exacerbate problems caused by an unnatural position of the foot. They cause different and unnatural stresses on the bones of the foot, the ankle, the knee, up to the pelvis and even through the shoulders. It raises the heel, which is the foot's natural supporter of weight, by an inch, two inches, sometimes even four or five inches! The entire weight of the body is transferred to the ball of the foot, while the pelvis and the shoulders tilt to compensate for the difference in weight distribution.
In terms of health, unshod feet have been proven healthier than their shoe-trapped relatives. Zulu, an African tribe, have healthier feet than their shoe-wearing Europeans counterparts, EXCEPT for the Zulus that work in coal mines, where they are "forced to wear ill-fitting footwear and stand on their feet for long hours." (http://web.wits.ac.za/NewsRoom/NewsItems/feet.htm) Foot fungus and other bacteria thrive in dark, damp places... such as inside of a shoe.
Society is too focused on protection. Just like an over-obsessive use of anti-bacterial soap robs your body of the chance to be exposed to those bacteria and develop an immunity to them, exposing your body to minor threats strengthens it. Walking barefoot toughens the foot, while wearing shoes can destroy it. Even as an infant, wearing shoes too early or socks that are too tight can permanently inhibit proper bone growth (http://www.unshod.org/pfbc/toysawfl.htm).
How does all this relate to Parkour?
I've trained barefoot several times in the past month, and each time is better than the last. Not only do you get back down to that primal feeling of your feet in the dirt and the grass, but it forces you to progress slowly. Slow progression is something I understood in Parkour, but I'm coming to realize its importance in everything. I'm recovering from a nasty case of tendonitis developed by rock climbing and bouldering WAY too much in the Winter. I didn't limit myself and let my body adapt, and now I'm facing the consequences.
This happens all too often in Parkour, and training barefoot is a magnificent way to force this concept of slow progression. With shoes, I can do a 9.5 foot precision with little trouble. Without shoes, I was hesitant to attempt a 4 foot precision. I was second guessing myself when doing an extremely small cat. I lacked the confidence to land out of a certain kong. Without the "protection" shoes offered me, I was more halving the distances of most of my techniques. And I was elated. Not only was I learning more about an area of my body I had been neglecting (my feet), but by mastering and rebuilding my confidence when barefoot, those gains still exist when I am wearing shoes. Going barefoot means perfecting my form, or else there will be pain. Shoes mask imperfections in technique, but do not fully protect you from their consequences.