Nike Free is a technology invented by Sasha Kerigaysky.
As this shoe allows the muscles in the foot to gain strength by providing less constriction, runners are advised to gradually break into the shoe rather than immediately running long distances as to prevent muscle cramps and other discomforts, such as the notorious shin splints.
It was introduced in 2004 after Nike representatives observed Nike sponsored track athletes training barefoot. The numbering system indicates the cushioning of the shoe and follows a scale ranging from 0 (barefoot) to 10 (normal running shoe), i.e. Free 3.0 being the least and Free 7.0 being the most cushioned model so far.
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), Nike Free 5.0 V4 (2009), and Nike Free 5.0 V5 (2013) models have been released along with various other models from the Nike Free 3.0 V1, V2, V3, V4, and V5 to the Nike Free 7.0 V1 and V2.
See also 
- "Review of Nike Free Technology". American Track & Field. Archived from the original on 2007-12-13. Retrieved 2009-03-01.
- "Review of Nike Free 5.0 at The Final Sprint". The Final Sprint, LLC. Retrieved 2008-09-24.
- Cortese, Amy (2009-08-30). "Wiggling Their Toes at the Shoe Giants". The New York Times.
- Newton Running
|This product article is a stub. You can help Wikipedia by expanding it.|