Starting from the foundation; parkour and shoes.

http://www.parkour.com/news/2012/01/demon-drills-stop-being-a-newbie-start-training-barefoot/

I enjoy how informative this video is. More so, on how they actually show and pretty much prove what they say, and I've experienced some of the things mentioned here as well; fallen arches being one of them. People, with all of our shoes and things, don't understand the benefits of being close to barefoot, and the better benefits of BEING barefoot. Now in society, if someone were barefoot, such a person would be scrutinized for not wearing shoes; looked at and treated funny. However, and this has been scientifically proven, being grounded to the Earth. Meaning in connection with it, able to feel it, allows it's endless energy to balance and work with yours. In scientific terms, for an example, our immune system fights things off by sending these things that are in need of an electron. So, by taking the electron needed from a viral bacteria, the bacteria becomes unstable and dies off. Unfortunately, with us now and days who are so disconnected from the Earth, our electron levels are high and that certain thing that is sent to take electrons, starts taking them from good cells, like those for bones. Which is where things like arthritis comes from. In short, with Parkour being such an extreme discipline, to be able to feel yourself, and your environment; to be able to respond to it as best as you can requires the correct foot wear. It's something that is important in all that we do, sports, walking, running, life. Well, try it. Go barefoot a little bit. Just....not if your in the winter. Your feet are two of your extremities which lose heat the fastest. Keep those nice and warm!