Under Armour | Convection Mapping for Shoe Uppers

Eden Millan, Fatima Garcia Corona, Isabelle Salzmann, Shannon Gill

As the shoe industry continues to evolve, it is more important than ever to prioritize breathability to maximize athletes’ comfort and performance. Our project was sponsored by Under Armour, and we were tasked with understanding what “breathability” really means – and making a shoe upper centered around it. Ultimately, “breathability” is the sweet spot of both air permeability and evaporative resistance (how air convects to evaporate sweat).

Our ideation process was inspired by life around us, from bike shoes to car hoods. Initially, we looked to use phase change material core-spun yarn for our prototype (what we called the “Icepack Shoe”), but after learning more about mechanical cooling, we opted for a design that takes advantage of an athlete’s stride to take in the most air possible for maximum convection (an iteration we called our “Moon Shoe”).

During the fall semester, we collected benchmark data from three Under Armour performance shoes. The shoes were tested at the Wilson College’s Textile Protection and Comfort Center (TPACC), using its hot plate to mimic the results of their sweating foot to analyze evaporative resistance and thermal heat transfer. We also disassembled the shoes to conduct air permeability tests and used both data sets to determine which shoe performed the best overall.

In January, we immediately ordered spacer mesh for our design and began to knit different samples for our upper. This was followed by a great deal of testing. Most of our time was spent analyzing our data and determining the relationship between air permeability and evaporative resistance so that we could select our final prototype structure. Finally, we were able to knit our upper so that we could last it to an outsole to create a finished, and breathable, shoe.

Through this project, we dove deep into the world of footwear heat management technology and were able to dabble in creating some technology of our own. We learned a tremendous amount about heat transfer from feet to shoes, defined breathability in working terms, and identified a relationship between air permeability and insulation. All these findings boiled down to the ultimate conclusion that the most “breathable” shoe would need to have a very thin upper as well as an air layer within the shoe which could be translated to extra room in the toe box.