Kicksology Terms 101
Surely you're interested about exactly how sneakers perform and function, but there's an entire world of terminology and technology that is used throughout the footwear industry.
So, study up and dive in to every term, phrase, tagline and more in our comprehensive Kicksology Terms 101.
General Foot & Shoe Terms:
arch: the portion of the bottom of the foot that does not touch the ground. The precise technical term is metatarsal arch.
ball: the swelling at the inner side of the foot where the big toe joins the head of the first metatarsal bone. This is the main line of flex for the foot and is sometimes referred to as the joint.
bespoke: a term used in several industries including fashion and automobiles, a bespoke shoe is one which is made to the precise measurements of a specific individual's foot. It is similiar in meaning to the term "made to measure."
Brannock device: invented in 1927 by Charles Brannock, it is a foot-measuring device featuring a slide piece adjustable to show the length of the foot and another slide piece which can be moved to show the distance of the ball of the foot from the heel. This measurement is used in conjunction with the foot length measurement to give the shoe size required. The device also indicates appropriate widths (learn more at brannock.com).
dorsum: the top of the foot.
dorsiflex: the upward flexing of the foot so that the upper portion of the foot (also known as the dorsum) approaches nearer to the leg.
insole: the light sole conforming to the shape of the bottom of the last. The upper and the midsole are attached to make the shoe.
last: a solid form of wood, plastic or metal on which a shoe is built, and which provides a shoe with its shape. When the sole has been attached the last is removed and the inside dimensions of the shoe should then conform to those of the last.
lateral: the outer side of the foot. An easy way to remember this is that when you are moving laterally, you are moving side-to-side.
medial: the inner side of the foot. An easy way to remember this is that the medial side of the foot is at the median line of the body.
midsole: the layer or material between the insole and the outsole of a shoe. In non-athletic shoes the midsole is generally made of leather or rubber, but in modern athletic shoes the midsole is usually made of a dense foam material such as EVA (see C in the image above).
plantar: the bottom or sole of the foot.
plantar fasciitis: this painful condition is caused by an inflammation of the thick, fibrous band of tissue that reaches from the heel to the toes.
plantar flex: the downward flexing of the foot so that the forefoot moves further away from the leg.
toe spring: the upward curvature or angle of the forepart of the sole relative to ground level when the shoe is on a level surface. Until recently it was assumed that a certain amount of toe spring was necessary to enable the wearer to proceed by a forward rolling action at the joint, but recent studies have challenged this assumption and many now believe that excessive toe spring actually inhibits the foot's natural ability to push-off using the toes (see E in the image above).
thermoplastic urethane (TPU): a plastic material which can be repeatedly softened and remolded by heat, but which retains its form at normal temperatures.
upper: the portion of a shoe that covers the upper surface of the foot. In the past the it was generally constructed of leather or fabric, but today, synthetic fabrics and materials are very commonly used.
The Upper of a Shoe:
counter: a shaped and molded stiffener, which is often found at the heel in basketball shoes, used to provide additional support for the heel of the foot. It is usually hidden between the material of the outer and inner lining, but in some shoes it is external to the shoe. Recent examples include the Nike Zoom Kobe IV and adidas adiZero Crazy Light.
Dynamic-fit sleeve: a Nike inner technology, it is a seamless inner sleeve made of Lycra which hugs the foot and ankle for improved comfort and support.
Foamposite: a Nike upper technology, it is made of polyurethane-based material and allows Nike to make a strong, relatively lightweight upper out of a single piece of molded material.
foot bed: an sockliner insert which is shaped or molded to match the approximate contours of the bottom of the foot. It is often made of a light foam material.
full-grain leather: from the top layer of the cow hide, full-grain leather is the strongest, most durable form of leather.
Lycra: the trade name for an elastic textile comprised of fibers made chiefly of polyurethane. The generic term for this material is spandex. Lycra is used as an upper material in some shoes and is a central component in Nike's dynamic-fit sleeve upper design.
monkey paw: a Nike technology, this is a thermoplastic urethane based structure that is usually contained between the inner lining and outer of a shoe and which provides an additional measure of ankle protection by preventing the ankle from excessive inward roll (also know as ankle inversion).
Neoprene: the trade name for the synthetic rubber, polychloroprene, developed by Du Pont in 1931. It is widely used as an adhesive in shoemaking and in soling compositions.
nubuck: a strong leather buffed on the grain side to create a velvety surface.
patent leather: leather which has been given a shiny finish. Originally this was applied using a linseed oil based dressing, but it is now usually plastic-based. A patent finish can be applied to leathers of widely differing qualities, so it can vary from light and supple to heavy and rigid. Of course, the Air Jordan XI is an example of its use.
suede: leather finished with a nappy surface through carefully controlled abrasion. Most modern athletic shoes use synthetic materials that simulate suede instead of the real deal for cost and ease of maintenance.
Flywire: a Nike upper material technology first introduced in 2008 in the Hyperdunk basketball shoe, Zoom Victory running shoe and Lunar Racer flat-inspired runner. A lightweight containment panelling inspired by bridge cables, Flywire is a three-layer package incorporating either mesh or TPU based outer and inner layers, with targeted strands of Vectran or Nylon to reinforce support.
The Midsole & Outsole of a Shoe:
adiPRENE: an adidas cushioning technology, adiPRENE is an elastic material which is designed to respond to the cushioning needs of the moving foot. adiPRENE is generally used in the heel.
adiPRENE+: an adidas cushioning technology, adiPRENE + is similiar to adiPRENE, but is more resilient and is designed to provide greater forefoot momentum at toe-off. adiPRENE + is used in the forefoot.
Air: a Nike cushioning technology, Air is now used in many different forms, but the word air is actually a misnomer. Invented by Marion Frank Rudy and introduced by Nike in 1979, Air-based shoes originally used pressurized gas encapsulated in polyurethane "bags." The molecules of gas are large enough that they do not pass through the polyurethane barrier. Nike's patent for Nike Air expired in 1997, allowing competitors to use air-based cushioning technologies, which many now do (for more on Nike Air see Charlie's Sneaker Pages).
Air, Blow Molded: a variation on Max Air in which gas is injected through an external tube, forcing the plastic Air unit into the shape of a mold. This allows the Air-Sole unit to take on a wider variety of shapes including the lower profile form used in the Air Jordan XVI.
Air, Encapsulated: Nike Air that is encapsulated within the midsole of the shoe. Encapsulated Air is not visible externally.
Air, Max: a Nike Air-sole unit which is shaped using air injected through an external tube (this is known as blow-molding). This allows more pressurized gas to be put inside bigger air bags providing even more cushioning. Another benefit is that Max Air-based shoes require less foam-based cushioning in the midsole, making it possible to have a lighter overall shoe. Max Air is usually externally visible and is used in both the forefoot and heel.
Air, Total: simply a Max Air-sole unit that runs the length of the midsole. The Total Foamposite Max features Total Air.
Air, Tuned: a variation on Max Air, which incorporates polyurethane based hemispheres placed in opposition to one another to provide added cushioning in specific areas of the shoe. The placement and thickness of the hemispheres is tuned to provide the maximum amount of cushioning precisely where it is needed, thus the name Tuned Air.
Air, Zoom: an advanced version of Nike's Air-based cushioning system that provides highly responsive cushioning in a very low-profile form factor. A Zoom Air-sole unit is made up of two layers of nylon fabric joined by densely packed fibers, which are sealed inside polyurethane. The unit is inflated; pushing apart the fabric and creating tension on the fibers. The combination of the air-pressure pushing out and nylon fibers pulling in creates something like a trampoline effect through the footstrike. Zoom Air is most often used in the forefoot of Nike's basketball shoes, but a few also make use of it in the heel.
DMX: a Reebok cushioning technology combining air-based cushioning with an air transfer system. Air transfer is achieved through the use of multiple interconnected air chambers, ranging from as high as 10 to as few as two in DMX i-Pak form. As the wearer exerts downward force on the DMX chambers through footstrike, air is transferred from heel to toe through the heel to toe transition. Reebok's basketball products make use of DMX in its i-Pak form. See our reviews of the Reebok Answer IV DMX and Reebok WINK DMX for examples of DMX-based shoes.
ethylene vinyl acetate (EVA): a chemical compound with rubbery properties that is very light in weight. The material's properties can be considerably modified according to the proportions of ethylene and vinyl acetate used in the copolymer. Many manufacturers use some form of EVA in the midsole of their shoes. (The adidas The Kobe above uses a compressed version of EVA in its midsole.)
flex grooves: areas carved out of outsoles and midsoles, usually at the area of the ball joint, to assure an anatomically correct response in the forefoot from footstrike through toe-off. This is a feature of almost all modern athletic shoes.
herringbone: the zigzag pattern used on many athletic shoe outsoles to provide traction with the playing surface.
Harmonix: an And 1 cushioning technology using bags filled with air at low pressure encased within a polyurethane skeleton. It is used in conjunction with And 1's Springz geometry to provide a high level of impact protection in the heel. This is a feature of almost all modern athletic shoes.
outsole: the outside sole of a shoe, the outsole is the portion of the sole that makes contact with the ground.
outrigger: a protruding extension of the midsole along the lateral side of the forefoot, commonly found in basketball shoes. The additional ledge of rubber helps a shoe from rolling over during harsh lateral cuts.
Phylon: a heated and compressed EVA foam cushioning compound that is light and resilient. Phylon is Nike's own patented version of EVA and is more dense than the standard fare due to the heating and compression. Phylon is usually used in the forefoot area of Nike's midsoles, but can also be used for the entire midsole.
polyurethane (PU): a very dense and durable foam-based material often used by Nike in the heel area of the midsole.
shank: a strip of steel, carbon fiber, thermoplastic urethane, wood or even leather, inserted between the outsole and the insole at the midfoot. In basketball shoes the shank provides additional support for the midfoot and keeps the forefoot and heel of the foot moving together.
SHOX: a Nike cushioning technology comprised of very high-density polyurethane foam columns formed and placed for sport specific applications. For basketball the columns are curved outward and scored on the inner sides, which allows the columns to deflect such that the heel is kept flat to the ground. This means that the SHOX system provides excellent stability, while also providing a high level of impact protection. See our review of the Nike SHOX BB4 for an example of a shoe using the SHOX cushioning system.
TORSION: an adidas stability technology, TORSION is designed to encourage natural rotation between the forefoot and heel while also providing midfoot support.
Zig Tech: a Reebok cushioning and transition technology first launched in the Zig Tech Pulse. With it's wavy appearance and slinky-like design, the system aims to transfer the wearer's energy through the shoe during stride.