Nike Free 2011 Training Women Yellow/Grey Shoes

Nike Free is a technology invented by Tobie Hatfield at Nike, Inc. and developed in conjunction with Gerard Hartmann and incorporated into some of their athletic shoes. Nike Free attempts to simulate barefoot running [1] while wearing a shoe.[2]It was introduced in 2004 after Nike representatives observed some of the track athletes supplied by them were training barefoot[4]. The numbering system indicates the cushioning of the shoe and follows a scale ranging from 1 (barefoot) to 12 (normal running shoe), i.e. Free 3.0 being the least and Free 7.0 being the most cushioned model so far.The Nike started the Free series with the Free 5.0 in 2005 and in 2006 released a new version of the shoe, the Nike Free 5.0 V2, that addressed some of the durability issues in the earlier model. Among other changes, the heel and sidewalls of the shoe were redesigned to prevent tearing.Since then, the Nike Free 5.0 V3 (2007) and Nike Free 5.0 V4 (2009) models have been released along with various other models from the Nike Free 3.0 V1 and V2 to the Nike Free 7.0 V1 and V2.