Anatomy
of a Running Shoe
Uppers
Shoes
with synthetic fabric uppers (the area that extends from the laces
down the side of the shoe to the sole) are lighter, washable and
breathable--so your feet don't get too hot. To lengthen the shoe's
life, wear them only for running and dry them slowly when they are
wet. Your running shoe should have a padded tongue to cushion against
lace pressure and a padded ankle collar to cushion the ankle and
help prevent Achilles tendinitis.
Midsoles
The
midsole is located between the outsole and the upper. It is the
most important part of any running shoe. It controls excessive foot
motion and provides cushioning and shock absorption.
The
primary materials used in midsoles are EVA (ethylene vinyl acetate)
and PU (polyurethane). EVA is a foam that is light and has good
cushioning, but breaks down fairly quickly. Compression-molded EVA
is harder but more durable. PU, also a foam, is denser, heavier,
and more durable than EVA.
Most
shoes are also cushioned with gel, foam or various manufacturer-specific
technologies that are encapsulated in the midsole. This cushioning
lasts longer than previous methods and often adds stability as well
as shock absorption.
Outsoles
The
outsole is the treaded layer glued to the bottom of the midsole.
It resists wear, provides traction, and absorbs shock. The outsole
is usually blown rubber, hard carbon rubber, or a combination. Blown
rubber is the lightest, but not as durable as carbon.
Stud
or waffle outsoles are good for running on dirt or grass because
they improve traction and stability. Ripple soles are better for
running on asphalt or cement surfaces.
Heels
The
heel counter is the inflexible material surrounding the heel. It
must be rigid and durable to support and stabilize the heel. Because
the internal heel counter material is thin and tends to lose its
stiffness, an external counter is usually placed between the midsole
and base of the heel counter.
A
wedge, which adds height to the heel, enhances the shoe's ability
to absorb shock and reduces strains. While this can ease problems
like Achilles tendinitis, a shoe with a higher heel may feel less
stable.
If
you're having trouble finding a running shoe appropriate for your
needs, check out The American Running's Running Shoe Database in
"Programs & Resources."
Copyright, The American Running Association.
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