Well (supposedly) they make a lot of things stronger. Knees, back, ankles, etc. They are made so that you are walking naturally as if you didn't have any shoes on, so instead of all the supportive stuff that all these new sneakers have, you have to support yourself with your own muscles. which are usually muscles that you don't use everyday thanks to these new fangled fancy shoes (nike shox as an example). Since you don't use them a lot, they are very weak, but thanks to Sanuk you can walk 'naturally' and build up those muscles.
Straight from the Sanuk website..
"The loose upper allows your foot to spread so it can absorb the shock naturally. This strengthens the small muscles which support your arch and encourages you to walk correctly. The shape of the bottom of the sandal is key as well: unlike many shoes which slant your body forward, our flat bottomed surfers allow your posture to remain erect."
Wow, I should be a rep or something.
