Earth shoes claim to naturally align your body and the secret is in the sole. The shoes all have an inclined negative heel technology and soles that feature a rocker design to promote a natural walking motion.
I have a pair of Earth Shoes but they are not the tennis shoe version. I have snow boots that are Earth Shoes. They are great. They make you feel like your standing in sand, your heals are lower then the balls of your feet. They are very comfortable, I want more. but they are a bit pricey.