After seeing this video you may throw your shoes away.

Harvard professor Daniel Lieberman has ditched his trainers and started running barefoot. His research shows that barefoot runners, who tend to land on their fore-foot, generate less impact shock than runners in sports shoes who land heel first. This makes barefoot running comfortable and could minimize running-related injuries.

Read more here http://www.nature.com/news/2010/100126/full/news.2010.36.html and find the original research here: http://dx.doi.org/10.1038/nature08723