The new ReactX foam from Nike offers greater energy return in a more sustainable manufacturing ... [+] method.
During the five-year process that resulted in Nike NKE releasing the brand’s ReactX foam as part of the InfinityRN 4 running shoe launch in July, senior product director Bret Schoolmeester says there were plenty of times the team thought about ditching the entire project and walking away. Pu Leather Sandals
There was nothing straightforward about crafting a new foam with the dual purpose of improved performance with superior sustainable manufacturing. But after five years the new ReactX foam debuts with an entirely original—and now proprietary—compound that allows for injection molding instead of compression molding, giving the ReactX foam an increase of 13% in energy return to the runner and a carbon footprint drop of 43% during the manufacturing process.
“We are hearing loud and clear from runners that they don’t want to make any compromises,” Schoolmeester says about the initial brief of a performance-plus-sustainability material. “So, that was really the challenge to the team, how do you get better at everything simultaneously? It was five years and it felt like 10 to 15 years packed in.
The Nike ReactX foam pairs with a Flyknit upper on the InfinityRN 4 shoe.
“It was not a linear process. It was very circuitous. Some days we felt like we are going to crush this thing and had a lot of points where it could have been logical to walk away, bin this one because it just doesn’t feel right.”
The first big energy-giving lift came after discovering a raw material that hadn’t previously been used in the athletic or footwear industry could potentially change the equation. Schoolmeester called it a “seminal moment” in the project that then led engineers to refine how they could make the material work for footwear.
Energy return comes as the goal for nearly every performance foam. With every step, energy is lost, making it hard to keep running. By offering up a product that returns energy to the athlete, it can help a runner achieve record times or simply feel good when exercising. To get that energy return, a material needs to come highly resilient.
A more durable outsole was required for the InfinityRN 4 thanks to the durability of the new ReactX ... [+] foam.
“To be able to do that and be able to be foamed lightweight enough in footwear is really rare,” Schoolmeester says. The new ReactX foam compound does them both, Nike claims, to make it work not just from performance, but sustainability, the team needed to make an impact by creating the material at scale. That’s where injection molding entered the conversation.
In a typical compression process common for high-performance footwear foams, engineers create a large piece of foam and compress it to its final shape. The foam’s memory keeps encouraging it to return to that larger shape. Injection molding starts with a hard piece and foams it into a final part, which traditionally doesn’t allow for great resiliency.
“With the compound being highly resilient, as well as tricks the chemical engineers pulled” the ReactX offers up the best of both worlds. And even better, Schoolmeester says, is it comes durable.
Once they felt they had it ready, it turned from an academic endeavor into a real-life test. “It is all out the door if runners and athletes say they don’t like it,” he says. Runners loved it.
Expect to see Nike roll out the ReactX foam in additional footwear models moving forward.
“Other foams feel lightweight or have good energy return for a little while, this really does hit the mark of highly resilient, really soft, a good weight score and it is going to last,” he says. At miles one through five Schoolmeester says it offers a leg up on competition based on feedback and lab testing, but the separation of the foam gets wider and wider the more miles it runs.
“We missed timelines, we pushed ourselves way past our normal comfort zones just to make sure we could make it happen,” Schoolmeester says. “The team pulled out several successive miracles to make it happen.”
Nike launched ReactX in the InfinityRN 4, a franchise known for a focus on cushioning, transition and stability. Paired with a more durable outsole to match the durability of the foam and the recycled Flyknit upper that “melts away” for comfort and offers minimal waste, the launch isn’t the only place Nike expects to roll out the ReactX.
Schoolmeester says there’s not a lot of limits to the foam. “React is one of our widely used foams and leads to a wide range of versatile uses,” he says. “Within running and across other fields, ReactX will be placed quite a bit over the next several years.”
Outdoor Moccasin Slippers Five years later, no one at Nike is tossing away the new ReactX project.