Nike first introduced the Nike Free shoe in 2005, bringing to life the concept of training barefoot to strengthen the feet and legs coupled with the protection and traction of a lightweight performance shoe.

"Not everyone has the luxury of a bare foot training environment like a pristine beach or a soft, grass field to experience the benefits of training barefoot. Nike Free allows athletes to experience these benefits in practically every environment," says Tobie Hatfield, Innovation Manager for the Nike Innovation Kitchen.

New for 2009 is a unique tongue construction that is engineered to reduce pressure over the top ridge of the foot, while also contributing added support by wrapping up around the medial arch.

Also new with the Nike Free 5.0 are bonded, soft, microfiber synthetic overlays inside the upper using ultra-sonic welding wherever possible creating a no-sew environment that maximizes comfort. These overlays are strategically placed to balance the fit, durability and support of the shoe with the dynamic flexibility of the foot in order to maintain the mobility and flexibility of being barefooted.

The changes to the Nike Free shoe since its introduction four years ago have been subtle yet significant to the performance of the shoe. While Nike has been working on the evolution of Nike Free, the architecture of a natural motion outsole has been adopted across a variety of performance footwear platforms including basketball, training, tennis, and with traditional running products.

"The interesting thing about Nike Free is that it really is for everybody," says Andreas Harlow, Global Creative Director for Nike's running footwear category. "We have elite athletes and average, every day athletes who use it regularly as a training device. Some would classify themselves as runners and some would consider themselves athletes of a different sport or sports who simply run as training for their sport."

The creation of the Nike Free shoe begins with the last which is the model around which a shoe is built. A traditional last is very flat with a pointed shape. The last for the Nike Free shoe is more contoured to emulate the shape of a bare foot. The materials and engineering that ultimately surround the last are designed to work together to continue the emulation of bare foot articulation.

Relative to the evolution of the Nike Free, Hatfield added, "We need to maintain a one-to-one ratio between the upper and the outsole, meaning that the flexibility of the outsole and the support of the upper must operate in concert - the outsole must always have the same degree of flexibility to the degree of support in the upper. One can never lead the other or the prospect of emulating bare foot running is compromised. We had evolved the outsole in the last two editions of Nike Free but the upper had not caught up until now."

The Nike Free 5.0 sits at the middle of the flexibility scale with 0.0 equating to running bare foot and a 10.0 equal to a standard running shoe such as the Nike Zoom Vomero. Nike also has a Nike Free 3.0 and the Nike Free Everyday which sits on the scale between the Nike Free 5.0 and the standard running shoe at 10.0.

The new Nike Free 5.0-specific upper provides just enough support while still allowing the foot to move in a natural, dynamic and barefoot-like manner.
Breathable mesh across most of the upper enhances comfort and ventilation while also providing a more barefoot-like fit and feel. Overlays are strategically-placed to balance the fit, durability and support of a shoe with the dynamic flexibility of the foot.

"You could call the design of the Free 5.0 a process-derived-aesthetic. We always make choices about the way things look," says Harlow. "The more honest you are with what you are doing - the processes and the goals - the more an aesthetic emerges from that and, in my opinion, the results look more compelling as a result."

The phylite mid-sole of the Nike Free 5.0 features a Waffle outsole construction for lightweight, resilient cushioning along with enhanced proprioception, traction and durability. The mid-sole also provides enough durability to double as an outsole, dramatically reducing overall weight.

Deep, gender-specific Nike Free sipes molded along the length and width of the mid-sole allow for barefoot-like flexibility and stability, while retaining the traction, underfoot protection and cushioning of a shoe. The Waffle outsole also encourages a more neutral and efficient toe-off.

Wider sipes, across the forefoot allow for greater engagement of the toes through propulsion for increased muscle activation and a more barefoot-like experience.

Inside the shoe, the molded sockliner mimics the curvature of the foot for a great fit, enhanced comfort and added support. Soft, durable foam inserts under the forefoot and heel provide added cushioning where needed.

The outsole is made of an abrasion-resistant, BRS 1000 carbon rubber under the crash pad enhancing the durability in this high-wear area, while strategically-placed segments of solid rubber enhance traction and durability at key wear zones.

The Nike Free 5.0 is available at retail globally, beginning May 2009.