The modern running shoe is a technical marvel, but the what and why of the wide array of shoes and their various technologies offered is more than a little bewildering.
Let’s break it down.
Your running shoe has three components: upper, midsole and outsole. Those 3 components, though, can be made up of dozens of individual parts assembled by machine and hand.
Let’s go from the top down, starting with the UPPER (A & B).
The upper of a running shoe is what keeps the shoe on your foot and most directly influences FIT. It includes the tongue, toe box, laces, heel cup and more. The shape and feel of the upper is also a deal-breaker in shoe selection. No matter how closely a shoe matches what you’re looking for, if the upper doesn’t just plain FIT, you’re not going to like the shoe. Upper materials can vary from open mesh, tightly woven synthetic material. Select Nike and adidas models made with Flyknit or Primeknit respectively, a proprietary stretchy knit of long threads. When you’re trying on shoes, the upper should fit so well that you hardly feel the shoe on your foot.
Next in our shoe survey is the is the MIDSOLE (C & D). The midsole forms the meat of the shoe sandwich and is the component that most directly affects how the shoes FEEL. The midsole sometimes includes a firm strobel board, firm EVA that attaches the upper to the midsoles, just under the removable sockliner (E). The difference in materials and the supplication of those materials is what makes some shoes feel soft and squishy and others feel firm and fast. You may not know which of these you prefer, or you may like different materials for different activities . The key here is to listen to your feet and talk to your fit professional to find your preferences. Most midsoles are composed of varying densities of EVA (Ethylene-Vinyl Acetate) that can be tuned to feel soft or firm and everywhere in between. adidas has pioneered the use of a new material, TPU (Thermoplastic Polyurethane) in its signature Boost shoes - this material has a springier and more responsive feel than most EVA midsoles. A great way to learn more about midsoles and what you like is to take advantage of as many shoe test-drives as possible. Make notes about what you liked and didn’t like about the shoes you tried. Your “shoe vocabulary” will improve exponentially. A note on sockliners: when you first slip on that new shoe, try to overlook the softness of the liner. Some shoes have very squishy liners that will lose that cushion quickly. Consider at least trying the shoe with a firm, supportive insole like Superfeet to see how the shoe feels with and without the sockliner.
We have arrived at the point “where the rubber meets the road:" the OUTSOLE. The outsole of the shoe gives traction, protection and durability by guarding against abrasion to the softer midsole. Midsoles are typically composed of either blown rubber (less durable but lighter and softer) or carbon rubber (more durable but harder). Some very light shoes (like the Saucony Kinvara or Hoka Clifton) use minimal outsole, applying only a few strategically placed sections of outsole and leaving the rest of the midsole exposed. If your top priority is light weight and a softer feel, check out these minimally covered models. If durability is of more concern then look for more coverage and a carbon rubber outsole.
Great shoes are more than the sum of their parts, and when matched up to the right foot (with the help of a trained professional) wearing them can be almost transcendent - the complicated assemblage of parts vanishing from awareness, allowing you to focus, or zone out, completely on your workout