The earliest foam can be traced back to 1929 by Dunlop Rubber when two chemists, E. A. Murphy and Eric Owen, used whipped latex to create the first rubber foam. This discovery eventually led to the creation of polymeric foam, or foams made from polymers such as plastic and rubber. Foam didn’t make its way on to a sneaker until 1974 when Bill Bowerman added a closed cell foam called EVA (short for ethylene vinyl acetate) to the midsole of the iconic Nike Waffle Racer. Closed cell foam, while very similar to open cell foam, is far less breathable yet much sturdier. Where closed cell foam is ideal for the midsole of a sneaker, open cell foam is great for uppers due to its light weight and breathability.

Since EVA’s inception, manufacturers continue to vary their ratio of raw materials—even playing with the molding, heating and cooling processes—to imbue various qualities. TPU (short for thermoplastic polyurethane) was invented shortly after, a material which possessed an element of durability and springiness. Nike’s earliest designs integrated EVA foam into the core of the sole. However, this was a time of minimalist running footwear—when some of the savviest runners proclaimed their love for running barefoot. Eventually, a majority of runners announced injuries due to a lack of support, padding and ease of motion, but EVA was still the best option given the technology available.

Nike’s foray into performance-enhancing foam began with Lunarlon. Searching for an ultra-lightweight foam that was both soft and bouncy, Nike designers Kevin Hoffer and Eric Avar unearthed a space-age foam from the Nike Advanced Material Interest Group’s closest. The material was a fusion of EVA foam with an elastic rubber called NBR (Nitrile Rubber). The technology debuted summer 2008 in Beijing in the form of two new shoes, the Nike Lunaracer for the marathon and the Nike Hyperdunk for basketball. Athletes praised how the sneaker could soften impact while providing support and springiness.

So why did Nike abandon Lunarlon technology in favor of React? The initial limitation with Lunarlon was the presence of a core of actual foam. A firm restraint needed to be added to the Lunarlon core, in turn adding a substantial amount of weight through stock fit assembly (when two pieces are glued together). The presence of the glue took away from the seamless experience of the sneaker. This is where the React sole comes into play. Due to increasing competition from adidas and its Ultra Boost sneaker, Nike needed a new technology it could implement into its future designs. Based on testimonials from thousands of runners, React is designed to soften the impact of each stride. “They [runners] want everything. They don’t want to sacrifice anything,” said Brett Schoolmeester. “Lunar was incredibly lightweight and it was very soft. So we really needed to maintain those, but how do we add energy return into it?”

The term “Energy return” wasn’t commonplace until 2013 when adidas unveiled its new cushioning system Boost. In fact, energy return is not even an actual concept. The energy for a stride comes from pushing one’s foot against the ground. Whenever anything soft is placed underfoot, it is essentially robbing energy. According to Martyn Shorten, Ph.D., a biomechanical expert, and director of the Runner’s World Shoe Lab, sneakers with traditional EVA foam tend to dissipate 40 to 60 percent of the force needed to compress them. However, newer innovations in foam lose only 30 percent of energy. Combined with a fashion-forward design approach, sales of Boost shoes allowed for double-digit growth in revenue, launching the brand back into the public eye.

The Nike React Hyperdunk 2017 and Jordan Super.Fly 2017 were the first in a burgeoning line of React footwear. The React foam was initially implemented in basketball sneakers due to its energy retention, making it perfect for swift movements and jumping. The Nike Epic React followed suit featuring a simple, knitted upper atop a single layer of extra-soft React foam. Ernest Kim, Director of Advanced Footwear at Nike Running said, “You not only get energy return—13 percent greater than Lunarlon—but a much softer experience as well.” The sneaker is even 30 percent lighter than Boost, giving Nike a strict edge in the weight department. React foam also quickly springs back to its original shape after undergoing pressure. Each step reacts swiftly to each preceding step, minimizing energy loss and bouncing back to its original state to ensure a constant underfoot. To top it off, Nike React technology is Nike’s longest-lasting foam.

While Nike successfully innovated the performance-enhancing qualities of its footwear, it was obvious adidas was a mile ahead in terms of fashion-forward, hyped—yet accessible—silhouettes. Even with lauded collaborations with the likes of Jun Takahashi and Riccardo Tisci, losing Kanye West to adidas proved to be a major detriment to the company. Thanks to Boost technology and a newly found partnership with West, adidas found a recipe for success in its Yeezy line and a wide array of Ultra Boost sneakers (also popularized by Ye at the time). The “Energy Surge” of 2013 propelled adidas in the ambiguous world of streetwear-meets-fashion, forcing Nike to respond.

With all eyes on Nike, it was time for the stalwart to make its next big move. After massively successful collaborations with Tom Sachs, Sean Wotherspoon and Virgil Abloh, Nike was on track to unveil its latest original design. Building on the transparent, revealing nature of Off-White’s “GHOSTING” Nikes, the retro yet modern aesthetic of the Mars Yard and Nike’s latest cushioning technology, Nike presented the React Element 87—a culmination of its latest and greatest advancements and aesthetics.

The starting point for the silhouette was derived from two simple objects: a slab of a foam and a drill. Designers and engineers began drilling holes into the foam, experimenting with different depths and foam densities to determine the ratio for optimal comfort. Using a tile—the graphic component of an equation—Nike designers successfully created an algorithmic pattern that could be applied to the outsole. A similar midsole was used for the Epic React, with a looser and wider pattern was utilized for the React Element 87. The tighter, stiffer pattern on the Epic React is performance-driven, while the newer pattern (seen on the React Element 87) is more suited for lifestyle activities.

When choosing the silhouette and materials of the shoe, Sportswear Innovation Designer Daryl Matthews looked to the original 1983 Nike Internationalist—specifically the tongue, toe and heel clip. The translucent upper and asymmetrical tongue also bare a strong resemblance to the Zoom Fly SP upper. “People are drawn to the shoe because it has layers,” said Matthews. Finished with suede detailing, rubber outsole pods, 3M accents, the Nike React logo and a 100 percent TPE yarn textile upper, the React Element 87 is a seamless intersection between old and new.

For the sneaker’s initial release, the React Element Element 87 was available in two colorways: “Sail/Bone” and “Anthracite.” The “Sail/Bone” bared a strong resemblance to the Tom Sachs Mars Yard, making it an instant cop among hypebeasts and sneakerheads, while the “Anthracite” colorway proved to be a hit among tech fans and avant-garde enthusiasts. Two additional colorways have since been released in addition to a well-received Undercover collaboration. An intriguing deconstructed iteration of the React Element 87 from Craig Green is also in the works, but a release date has not been announced. With a slew of fast-paced releases, it is clear Nike has big plans in mind for the React Element 87.

Following the success of the React Element 87, Nike released a general release model: the React Element 55. While the silhouette is indisputably similar to its parent model, the React Element 55 utilizes materials found on mainline Nike runners. In absence of translucent TPE, a synthetic textile upper is featured atop a React sole. Other key 87 details—3M, leather hits and an asymmetrical tongue—are also absent, no doubt a cost-saving measure. So far, four colorways have been released; if the popularity of the 87 is anything to go by, the React Element 55 is on track to become Nike’s next casual staple.

Succeeding a myriad of React footwear, the sportswear stalwart recently announced another iteration of the popular sneaker—a mid-top silhouette dubbed the React Runner Mid WR ISPA. The sneaker features a more utilitarian impression (akin to Nike ACG) with rope laces, piping overlaying the seams, contrast side stitching, overlapping swooshes, a tab connecting the midsole to the ankle collar, and of course, React cushioning. Between the React Element 87 and 55 and the React Runner MID WR ISPA, React technology is becoming a staple hallmark for Nike's most lauded offerings.

Despite recent forays into fashion, Nike’s singular focus has been—and always will be—its pioneering, athlete-inspired technology. React technology is at the heart of this ethos. While adidas may have taken a momentary cultural lead, Nike will continue to do what it has always done: innovate. In the midst of a “foam revolution,” Nike, through the React, reminds us why it stands where it stands... and precisely why it matters.