“This town ain’t big enough for the two of us.” Instead of the customary hello between two strangers as they meet for the first time, I’m inclined to think that Woody would have told Buzz Lightyear to “Buzz off!” had he known at the time how this upstart space toy would create chaos in his calm universe, i.e. Andy’s bedroom. Toy Story, the acclaimed 1995 film that introduced us to the lovable toys Woody and Buzz, is a window into changing times. Call it old versus new. Or the past pitted against the present. Or as Bob Dylan once exclaimed many years ago, “The times they are a-changin.”
Incidentally, the times are changing for running shoes too – particularly the midsole. EVA, or ethylene vinyl acetate, has functioned as a mainstay midsole for the past few decades. Unfortunately, the process of producing just one is complex, tedious, and wasteful. Florence Williams, author of a 2008 Runner’s World article, describes the structure of EVA and the environmental impact it exacts. “To be bouncy and light, the foam is made from a matrix of polymeric cells with entrapped gas. But running makes the foam flex and compress; over time, the walls of this matrix break down and the cells flatten out. Then you need new shoes.”
Runners need new shoes indeed. According to a 2013 Guardian article, more than 25 billion pairs of shoes are manufactured each year. What’s more, they have a short shelf life. Suzanne Goldberg, author of the article, highlights a study by MIT researchers that shows a running shoe to be the source of 30lbs of carbon dioxide emissions. Yikes. Furthermore, since runners require shoes on a regular basis (e.g. 3-4 months) to replace the deceased ones, haste from manufacturers to keep up with a strong demand is producing a hefty pile of waste. What’s the solution, if any?
Enter TPU, or thermoplastic polyurethane, and Adidas, the German sportswear behemoth. In 2013, Adidas introduced a revolutionary running shoe, aptly named the Energy Boost. In partnership with BASF, the German chemical company, the Boost quickly disrupted the footwear market. A shoe with greater energy return? A shoe more resistant to temperature change? A shoe that yields more total mileage before breaking down? What runner is unwilling to answer with a resounding yes to these three questions? Like others intrigued with the Energy Boost at the time, I tried a pair and liked them – a lot.
I see EVA and TPU as the Woody and Buzz of the running universe. They occupy a large space, but I suspect that they don’t play together well. In other words, runners pick their favorite shoe, often based on the midsole, and shrug off the others. If you recall Toy Story, Woody and Buzz feuded to the point that circumstances became dire and they were forced to work together to escape the vicious neighbor Sid. Do EVA and TPU need one another though? Can they co-exist? If you study running shoe models closely, the evidence is there. A number of Adidas models utilize both midsole compounds in the midsole. Saucony is doing this too as they roll out EVERUN into their footwear collection. But a question emerges: will a midsole like TPU address the waste issue if it means that less shoes need to be manufactured? Think just-in-time inventory.
In the words of Florence Williams, “The midsole must be all things to all people, delivering everything from durability to comfort to energy return. But if midsoles are the technical wonder of the shoe, they are also its main environmental culprit.” Translation? Innovation. Reclamation. Transformation. The aim of running shoe companies must be focused on developing a shoe that lasts longer and places less strain on the environment. Is this doable? Without question. Will it take time? Without question.
The future of running shoes is bright, and it’s surely bouncy, full of energy return. Unsurprisingly, Adidas appears to be leading the way towards this through the use of 3-D printing. Here’s Dennis Green of Business Insider on the Futurecraft 3D. “The shoe would be a completely flexible, exact copy of the runner’s footprint – matching the foot’s exact grooves, instep, and contours.” In other words, the shoe is as unique as the foot that will wear it for many miles. Will a process like this, 3-D printed shoes, lead to less midsole waste in the landfill? Time will tell, and I’m also optimistic that the now hefty cost will drop too in the coming years.
Though Adidas is dabbling with 3-D printing, Nike and New Balance are following suit as everyone wants a piece of the futuristic pie. Speaking of Nike, they have undoubtedly contributed to simplifying the running shoe upper courtesy of FlyKnit (Adidas uses Primeknit). Fabric waste has surely dropped by way of this innovative practice. Remember the earlier reference to just-in-time inventory? Should 3-D printed running shoes attain a strong presence in the footwear market, this might be the ideal approach from a production standpoint. Kieran Alger agrees. “The brands will only need to make the shoes they actually sell. That’s good news for the bottom line, cutting wastage cost from unsold products. It’s also great for the environment, another big agenda item for the increasingly ecoconscious megabrands.” This is environmental stewardship for this planet, and the ones beyond.