Shoe Review: Nike Epic React Flyknit

We put this innovative new shoe with a revolutionary midsole foam to the test

Price: $150

Specs: Men’s (size 10): 18mm (forefoot), 27mm (heel), 9mm heel-toe offset; Women’s (size 8): 12mm (forefoot), 22mm (heel), 10mm heel-toe offset.

Weight: Men’s (size 10): 8.45 oz. Women’s (size 8.0): not supplied

The Scoop: Footwear giant Nike has been surprisingly slow to jump on the “energy return” bandwagon, first made popular by Adidas’s Boost line that launched five years ago. As might be expected, however, rather than launching a “me too” product, Nike has been busy in the lab creating something new in the category. Their Nike Epic React, which hit stores Feb. 22, breaks new ground by delivering not only top-shelf cushioning combined with exceptional energy return, but does so on a lightweight platform. Instead of starting with notoriously heavy polyurethane foam like other energy-return midsoles, React foam is based on a synthetic rubber and represents an entirely new chemistry for Nike and the industry.

In addition to its performance qualities, Nike touts React’s longevity. They admit that most foams, including their own Lunarlon, start to lose their cushioning and bouncy feel after about 150 miles. In contrast, React, they say, tested like new even after 500 miles, both in the lab and on runners’ feet. “We took wear-test shoes that already had 500 miles of wear on them, cleaned them up and put them on wear testers,” says Footwear Innovation Director Ernest Kim. After running a loop of the Nike campus, about a 5K, Nike asked testers how many miles they thought were on this shoe. “The biggest guess? 20 miles,” Kim reports.

The Epic React showcases the new foam in a simple, single-layer midsole with a thin rubber outsole covering only the heel and toe. Wavy grooves cut into the sides and bottom of the midsole are computer-designed to create areas of greater cushion—such as along the diagonal mid-line from the outside of the heel to the first-toe joint—and areas of greater support, e.g., on the inside of the heel and the outside of the ball. A u-shaped plastic clip surrounds the base of the heel counter and adds a touch more rearfoot stability.

Who’s it best for? Nike designers intended for React to be a “democratic innovation.” Unlike their firm, fast Zoom X that is tuned for elite speed, React has a softer, more forgiving feel while still delivering a decidedly responsive and lightweight ride. “We wanted React to be something that would help the everyday runners of the world,” Kim says.

Our wear testers confirmed the shoe’s versatility: While bouncy is the foam’s primary personality, it is also comfortable and cushy, and the 9mm heel-toe drop with an aggressive toe-spring rolled along nicely at any pace. The shoes felt fast, popping off the toes quickly during 400m repeats at 5K pace, yet also held their own in comfort and protection on easy 10 milers. That said, most runners will think of these as lightweight, neutral trainers for casual runs or up-tempo days, while only speedsters will rack up lots of miles on them. Reportedly Nike elites Eliud Kipchoge, Evan Jager and Shalane Flanagan have been enjoying prototypes on their easy runs.

Plus: “React is all about delivering this combination of plush with energy return that is going to last a long time,” says Kim. That’s true of all energy-return foams, but the Epic React delivers it in a far lighter package and faster-feeling ride than we’ve tested to date.

Minus: The tight-fitting, minimally-padded FlyKnit upper can be either a strength or the one weakness of the shoe. Stretchy and forgiving in the forefoot and snug and supportive around the instep and ankle, it slips on easy and disappears—if it fits. The lacing is not very adaptable, however, and the fit of the ankle and heel collar is tight and can make the shoe hard to get on. The unpadded heel counter was also a bit finicky and rubbed some testers. Nike says they’ll offer another shoe this summer, the Odyssey, with the same midsole foam but a more conventional upper, and an even more accessible $120 price tag.

Watch this video from Nike to learn more about the new React foam.

Jonathan Beverly
Jonathan Beverly served as the editor in chief of Running Times from 2000-2015. He is the author of "Your Best Stride: How to Optimize Your Natural Running Form to Run Easier, Farther, and Faster—With Fewer Injuries" (2017, Rodale) and "Run Strong, Stay Hungry: 9 Keys to Staying in the Race" (2017, Velo Press).