For access to all of our training, gear, and race coverage, plus exclusive training plans, FinisherPix photos, event discounts, and GPS apps, sign up for Outside+.
Those dedicated and understanding footwear salespeople really want to help you find the best shoe. But it may seem as if they are talking another language. Here are some key terms and explanations that will help you talk the talk to better run the run, so to speak.
Neutral or Motion Control Running Shoes
The Basics: Pronation is a natural part of a runner’s gait cycle, but for some that motion is more pronounced and causes instability, leading to repetitive motion injuries, especially in the knees. A shoe can have motion control or be “neutral” to allow you to go through your natural gait cycle uninfluenced.
History Lesson: Stability shoes of the past were blocky and forced the foot’s cycle. The modern approach is a less intrusive, gentler and suggestive technique.
Extra Credit: Motion control, also known as stability shoes, uses various strategic mechanical devices like posts, plastic or midsole zone construction to minimize the foot’s lateral movement.
Midsole in Running Shoes
The Basics: This section between the outsole (which is the tread part that comes in contact with the ground) and insole (which is the liner on which your feet rest) is where the magic happens. It is where all the cushioning, protection, rebound and dampening occurs.
History Lesson: Midsoles have been made from ethylene vinyl acetate (EVA) and/or polyurethane (PU). EVA tends to be light and flexible, but loses those qualities faster than PU, which is heavier, firmer and more durable. Shoe companies vary the EVA densities and hardness—which is called “durometer”—and mix in PU and a compression molding process to extend the midsole life. Now encapsulated foam technologies (like in the Adidas Boost) allow for even more midsole variations.
Extra Credit: Manufacturers also place air, gel and other cushioning units as well as new support and motion-control technologies in the insole.
Drop in Running Shoes
The Basics: This is the height differential, measured in millimeters, between the shoe’s heel and forefoot.
History Lesson: It used to be standard to find 9–12mm offsets, but thanks to the “minimalist” movement, the norm these days is closer to 6–8mm, but some shoes are “zero drop”—closest to the angle of being barefoot.
Extra Credit: The total measure of the thickness, or “stack height,” may include the outsole and insole, but it will always encompass the midsole.