From its introduction in 2004, the idea of the Nike Free, as the name suggests, was to let the foot move as it wished. The principle was that a shoe should act as an extension of the foot, enhancing its cushioning properties but not interfering with or trying to control any of its motion. Nike’s new Free RN Motion ($150), which the company will roll out on May 5, takes this concept to a new level.
One of the challenges of making a shoe fit is that the foot’s shape is not static. As you move through the stride the arch lengthens and flattens, the toes splay and flex, the instep arches upward. These changes are not insignificant. “In our research on foot movement, we found that the foot is expanding in both directions—medial and lateral—up to two sizes in width and an entire size in length,” says Chuck Gatchell, VP Run Natural at Nike.
The best most shoes can do to accommodate this movement is to bend at the right places and to not restrict the foot’s expansion by being longer and wider. The Free RN Motion goes one step farther. Rather than flex grooves, the sole is molded in interconnected geometric shapes that push and pull on each other as the shoe flexes. Unlike most materials that get narrower as they stretch—think about pulling a ball of bubble gum out of your mouth—this sole displays auxetic properties: the accordion-like ability to widen as it stretches. Just like the foot, the sole of the Free RN Motion gets both longer and wider as it moves through the stride. The shapes, angles and spaces of the midsole molding differ in each part of the sole, matching the movement and purpose of each region of the foot.
In addition to the new flex properties, this Free RN Motion has a two-layer midsole, co-molded so they act as one unit, similar to the Free RN Distance released last year. A bouncy core of rubber-infused Lunar foam sits on inside, just beneath the foot. Wrapping it is the flexible IU foam that has formed the sole of all Frees. Stack heights fall between the previous Free 3.0 and 4.0, with approximately a 4mm heel-toe drop. The top of the midsole is contoured such that the foot sits within a molded sidewall that extends higher under the arch.
The stretchy Flyknit upper completes the molds-to-your-foot feel. What Nike is calling a 3D Flyknit, the sock-like material has raised ribs wrapping across the foot from midfoot to toe, provide a minimal structure to hold the foot without restricting any of its motion. The heel wrap is soft, with no controlling structure—one of the core characteristics of Nike’s “natural” line—topped with a thin, stretchy ankle cuff with a convenient split overlap in front for ease of entry. Underfoot the strobel—the layer between your foot and the sole that ties the upper down—is as thin and flexible as the upper, not restricting the shoe’s movement or blocking the feel of the bouncy foam beneath.
After a few runs in them, I can say that the shoe performs as promised. Whereas in most shoes, even minimalist ones, you can feel movement of your foot within the shoe under the arch, ball and toes, the Free RN Motion stays next to the skin, above and below the foot, throughout the full stride. I wore them having a few blisters and hot spots from a long run in other shoes and quickly forgot which part of my skin was sore as there was no friction between the shoe and my foot.
The sole felt like it was expanding and moving like an extended bottom of my foot—closer than any shoe to date of having simply grown an extra inch of padding. The sole moved so well with my foot I almost felt I could pick up a towel with my toes while wearing them. I felt in touch with the ground, interacting with it without any interfering angles or forces.
And yet the shoe didn’t feel minimal—the cushioning underfoot is enough so you don’t have to brace yourself for touchdown on any surface, but they don’t feel at all marshmallowy. They performed nimbly doing 200ms at mile pace on the track, and felt comfortable and supportive on an easy 7.5-miler over concrete, dirt and metal bridge grates. The geometries of the sole provide a subtle stability that makes them feel more mainstream than expected when on the run.
Bottom line is a shoe that should please fans of the Free line and may attract others from both ends of the spectrum—those who felt the Frees weren’t minimal enough and those who didn’t think they could run in Frees.