Glossary of Common Shoe Terms

By: The Mizuno Shoe Guy


 Did you feel totally lost the last time you went to a running store to shop for a good pair of shoes? The sales people were probably helpful and well-intentioned, but you might have felt they were speaking a different language with all sorts of technical shoe lingo.


No wonder. There are so many shoe terms and technological fancy-talk in the running world that it might as well be a different language.


Don’t despair. We’re here to help you decipher the shoe language.


Most of the common shoe terms are actually rather simple to get the hang of. A basic understanding of them is always helpful to fully appreciate the special features of each shoe you may be looking at.


Here are the most important terms and what each one means:



Adjustable width lacing is a system of webbing rings to secure the lacing of the upper. Also called speed lacing.


Airmesh is a Mizuno lightweight upper material that maximizes breathability and comfort. Used on all Mizuno shoes.


Blown rubber is a type of outsole common to many running shoes. Blown rubber is a rubber compound which is either expanded or mixed with air in the production process to produce a relatively light, cushier outsole but one that is less durable than carbon rubber. Some shoes, including the Mizuno Wave Enigma 5, use a combination of blown rubber in the midfoot and forefoot (for a pillow-like ride) with carbon rubber in the rearfoot for added durability.


Board last is a thick fiberboard material which a shoe’s upper is glued to in the manufacturing process. The fiberboard is visible in the heel of the shoe underneath the insole.


Carbon rubber is the most common outsole. It is a solid rubber with carbon added to increase the durability of the outsole. A carbon rubber outsole is firmer and heavier than blown rubber, but also more durable than blown rubber.


Cushioned (or neutral) shoes are a category of shoes that emphasize maximum midsole cushioning and minimize support features. Cushioned or neutral shoes (the terms are synonymous) are preferred by runners who don’t have abnormal rearfoot motion (overpronation). Top Mizuno cushioned neutral shoes include the Wave Enigma, Wave Rider, Wave Creation and Wave Prophecy.


Cushioning is the act of absorbing energy by the shoe when the foot contacts the ground.


DynamotionFit is a Mizuno upper technology which reduces stress that the foot places on footwear. Found in all Mizuno shoes.


EVA is the acronym for ethylene vinyl acetate which is the most common commercially manufactured midsole foam used in running shoes. Different shoe brands have different names for this material. It is sometimes referred to as CMEVA or compression-molded EVA because in the manufacturing process the foam is heated and compressed to give it shape.


Flex grooves are notches (or grooves) sliced into the midsole/outsole in the forefoot that allow the shoe to bend with the foot at toe off. Almost all high quality running shoes use flex grooves that allow the foot to roll more naturally at toe off.


Gender engineering adjusts to the differences in the running styles and feet of men and women and how it’s reflected in Mizuno men’s and women’s running shoes.


Heel counter is a plastic cup built within the upper which cups the heel to reduce excessive rearfoot motion. The heel should fit snugly without being too tight. If it’s too wide, the heel will slip in and out of the shoe and cause blisters.


Heel heights are the height at which the foot sits on top of the midsole and outsole. Heel heights vary from shoe to shoe and brand to brand but generally, a bigger, slower runner (especially a heel striker) wants more midsole foam for better cushioning which means a greater (or higher) heel height. Faster, more efficient runners tend to strike more in the midfoot or even forefoot and usually prefer a lower heel height. A lower heel height promotes stability, but a higher heel height adds cushioning and takes some of the strain off the Achilles and calf muscles. Training shoes have the highest heel heights; racing shoes the lowest. Conventional heel-to-toe ramps (the difference in height from heel to forefoot) are 12 millimeters for most Mizuno training shoes, while some lightweight trainers are anywhere from 10 millimeters to six for the lightest racing flats.


Last is a term you might hear in the shoe store and it is very confusing because it can refer to two entirely different things. The most important reference is to the shape of the shoe. A last is a shaped piece of wood or metal on which the shoe is actually built. Different shoes use different lasts (especially different brands) which is why shoes fit differently.



Last can also refer to how a shoe is lasted or how the upper is attached (sewn actually) to the midsole. There are three ways: combination-lasted, slip-lasted or board-lasted. A slip-lasted shoe is entirely stitched, whereas a combination lasted shoe is stitched in the forefoot and glued in the rearfoot with a fiberboard. A board-lasted shoe has a fiberboard glued on top of the midsole. Slip-lasting is the most common although some brands still use a combination last in some of its shoes. Some runners believe a combination-lasted shoe is the most stable and most supportive for orthotics but it is personal preference. (Board-lasted shoes have gone the way of the dinosaur.) To determine which type of lasting the shoe has, remove the insole. If there’s stitching in the rearfoot, it’s slip-lasted. If there’s a fiberboard (a cardboard-like material) on top of the midsole and stitching in the forefoot, it’s combination-lasted. When in doubt, ask.


Lateral is in reference to the outer edge of a shoe. Or, the side of the shoe opposite the arch.


Medial side is the opposite of the lateral side. It’s the arch side (or inner side) of the shoe. The medial side is the side of the shoe where most stability devices are located.


Midsole post is also known as a medial post or two-density midsole. It refers to a firmer density of midsole material on the medial side which reduces overpronation. Almost all brands—Mizuno being the exception–use a midsole post in at least some of its trainers. Instead of a midsole post, Mizuno uses its Wave technology to stabilize the foot.


Midsole is the light colored foam your foot rests upon which cushions the foot. The midsole is the most important part of the shoe because of its cushioning responsibilities. The midsole is located between the shoe’s upper and its outsole and is attached to both.


Motion control is a type of shoe which is designed to reduce excessive inward foot motion—overpronation. Motion-control shoes are usually the most expensive, heaviest and most protective shoes because they employ the most control and stability features.

Overpronators and many big, heavy runners do best in maximum-control shoes such as the Mizuno Wave Paradox.


Outsole is the black material on the bottom of the shoe which contacts the ground. The outsole provides traction and durability for the shoe.


Overlays are straps built into (or stitched into) the shoe’s upper, usually in the midfoot and forefoot, that provide support and reinforcement.


Overpronation is the distinctive inward roll when the foot hits the ground and the arch collapses. Some pronation is a good thing (it absorbs shock), but too much beyond a certain degree can lead to a variety of injuries if left unchecked. Most overpronators need support or motion control shoes such as the Mizuno Wave Inspire or Wave Paradox.


Post is an interchangeable term with a two-density midsole or midsole post.


Pronation is the natural inward roll of the foot which occurs at heel strike. Pronation is the lower body’s way of cushioning with each foot strike at impact. Some pronation is normal; too much is considered overpronation. Not enough is considered underpronation.


Racing shoes are the lightest, most flexible type of running shoe. Some racing shoes are half the weight of typical training shoes, but offer much less in terms of cushioning, protection and durability. Generally, only runners racing at 7-minute pace or faster and who are biomechanically efficient in their gait (i.e., they don’t overpronate) should consider racing shoes. Mizuno racing shoes include the Wave Hitogami, Wave Sayanora and Wave Ekiden.


Seamless uppers are shoes that don’t have seams that may irritate the foot. Seamless uppers are also highly breathable and light.


Sockliner (or insole) are synonymous terms that refer to a light footbed that sits on top of the midsole under the foot and provides comfort. All Mizuno shoes have removeable sockliners.



Stability shoes are the most common type of training shoes. Stability (or support) shoes usually have a two-density midsole and a stable base of support to reduce overpronation. (Again, Mizuno doesn’t use two-density midsoles.) Some of the most popular (and best) shoes on the market fall into the stability shoe category, such as the Mizuno Wave Inspire.


Stack height is the distance from where the shoe lies flat on the ground to the top of the shoe’s midsole. There are two basic stack heights: the heel and forefoot. The difference in height between the heel and forefoot is the shoe’s ramp or drop.


Supination is the opposite of pronation and much less common. It is the outward rotation of the foot or ankle. Also, commonly called underpronation because the foot doesn’t pronate enough to absorb shock.


Toe box refers to a plastic piece in the toe of the upper which maintains the shape of the shoe and improves durability in this area. The toe box is the front of the shoe’s upper which encases the toes.


Two-density midsole means the same as a midsole post or simply, a post. It’s a second, firmer density of midsole material on the medial side which reduces overpronation. The second, firmer density is usually a darker material on the medial side just above the arch area.


Upper is the synthetic and mesh portion of the shoe which covers and fits the foot.


U4ic is Mizuno’s proprietary midsole material used in Mizuno running shoes. It’s a light, cushioned material with good durability qualities.


U4icX is an even lighter iteration of U4ic which provides a softer underfoot feel. Used in the Wave Enigma.


Wave Plate is a proprietary technology only used in Mizuno shoes. The Wave is a plastic material inserted between the midsole and outsole which cushions and stabilizes the foot. The light Wave plate does not break down or degrade over time or with use. There are different Wave plates for different Mizuno shoes, including Parallel Wave, Double Fan Wave, Fan Wave and Infinity Wave.


Width sizing refers to different widths. The most common men’s width is a “D” width and women’s “B” width. But Mizuno also offers a wider width (“EE”) for men in selected models and a narrow (“AA”) and wider width (“D”) for women in selected models.


X10 is a Mizuno brand name for the most durable carbon rubber used in the outsoles.