Running shoes are designed for a forward motion and cushion the impact specific to running. Running shoes typically have less lateral support, which is fine for running as you are not quickly changing direction. Cross trainers are designed with more lateral support and toe flexibility which suits activities where you are going to cut or change direction quickly the added lateral support overcomes the likely hood of ankle injuries.
The running shoe comprises of three main components:
Outer Sole
This is the bottom of the shoe. It is usually made of carbon runner or blown rubber. Carbon rubber is durable, somewhat stiff and relatively heavy material used for outsoles. Blown rubber is lighter weight, more cushioned and flexible
rubber used for outsoles. It is made by injecting air into a rubber compound.
Construction
"Flex grooves: Grooves cut horizontally across the forefoot of the outsole that allow the foot to flex at the ball of the foot (its natural bending point)and roll more naturally.
"Split heel: The heel of most running shoes is flared and split into 2 sections, an outer and an inner piece. This makes the heel-to-toe running
motion more efficient.
Midsole
The layer of soft, shock-absorbing material between the outsole and the upper. This is the most important part of a running shoe, because the construction and materials used will impact the levels of both cushioning and motion control/stability in the shoe. The amount of cushioning in the shoe is generally proportionate with the shoes heel height. The two types of
cushioning generally found in running shoes are EVA and Polyurethane. EVA is lightweight cushioning, not too much stability and durability. EVA can be compressed to make it somewhat more durable. Polyurethane (PU) is more dense and durable cushioning material. PU can add stability to the shoe, but also adds weight.
Stiff materials, usually in the form of a medial post or a footbridge, are used in some shoes on the medial or inner side of the shoe to reduce over pronation or excessive inward rolling of the foot. Heavier densities of cushioning materials may also be used in the medial area to increase a shoes stability.
Upper
This is the soft body of the shoe. Usually made of a combination of materials, from lightweight, durable synthetic mesh to heavier materials like leather. The materials and construction of the upper provide stability, comfort, and a snug, but not tight, fit. Features to consider in the upper include the following:
Last: This is the basic shape of the shoe. Running shoes have one of three basic categories of lasts: straight, semi-curved and curved.
Toe box: The front part of the shoe. This should provide ample room to allow the foot to flex and make the toe-off portion of the running motion comfortable. A toe box that is too small will restrict the muscles and tendons in the foot and lead to pain and cramping. As a general rule, you should have about S an inch (about a thumbs width) between your longest toe and the front
of the shoe.
Heel counter: A plastic or composite material used to reinforce the heel area and increase stability. Heel counters come in varying degrees of stiffness. An external heel counter generally provides the most motion control and stability.
Achilles notch: A groove in the back of the heel collar that protects the Achilles tendon. Prevents irritation to the Achilles tendon. Contributes to a snug, secure fit.
About The Author
Tom Sneddon is a contributing author and publisher to
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