Transcript Choosing the Correct Shoe

Paul Thawley MSc
Choosing the Correct Shoe
Definitions
 Last: The template or model
upon which the shoe is built.
Different manufacturers use
different lasts.
Definitions (cont.)
 3) Outsole: Has tread for
traction, flex grooves for
flexibility, protects from dirt
and rocks. Made of two
materials:
 Carbon rubber (durable same material as tires)
 Blown rubber (lighter, more
flexible, more cushioned, not
as durable). Blown rubber is
rubber with air
injected into it (blowing a
bubble with chewing gum)
 Outer-Sole: The
outermost part of the
sole, which is treaded.
On running shoes the
tread is designed for
straight ahead motion.
Court shoes and cross
trainers have their tread
optimized for lateral or
side-to-side stability.
Definitions (cont.)
 Upper: The uppermost part
of the shoe. This part
encompasses your foot and
has the laces.
 1) Upper: Holds the foot in
place, protects the foot from
rocks and dirt, has synthetic
leather for durability, mesh
for breathability and
reflective material for safety.
Definitions (cont.)

2) Midsole: Most important part of shoe.
There are three materials that make up
the midsole:

EVA - lightweight, foam-based
cushioning

Dual-density EVA:
 What happens when you double the
 Midsole: The portion between
the upper and the outer-sole.
This is the area whose major
contribution to the shoe is shock
absorption. It is also usually
quite important that the midsole
be stable from the heel until the
distal third of the shoe where it
should be flexible at the point
where your toes attach to the
foot and bend.




density of something? It gets stronger,
firmer, heavier (twice the mass in the same
amount of space)
We call this dual-density EVA a "medial
post"
Medial - because it is on the inside of the
shoe
Post - because it has a beginning and an
end. The length of the post determines the
amount of control
Polyurethane:
 very durable cushioning
 More durable/stable than EVA, weighs
more than EVA.
Definitions (cont.)
 Counter: A rigid piece
surrounding the heel that
provides some stability.
Look at your old shoes

Examine the soles of your shoes. Note where wear has
occurred. Most people walk and run with their feet
slightly rotated from center. Runners, however, also
have what is called a narrow base of gait. A narrow
base of gait means that the feet contact close to the
midline of your body. This creates additional varus
(tilting in) of the limb. This results, for the rearfoot striker,
in the first point hitting the ground being the outer corner
of your shoe.

Forefoot wear may point to an individual who is a
sprinter, runs fast, contacts the ground with the forefoot
first or all of the above. Uneven forefoot wear may show
where one metatarsal is plantarflexed relative to the
others or where one metatarsal may be longer than the
others. In the presence of significant forefoot wear, you
are at risk of stress fractures.
RUNNING SHOE FIT
 Running shoes don't need to be broken in.
They are made of synthetic materials that
DON'T stretch, and the cushioning is ready to
go, so they fit "right out of the box".
The way they fit the first time is the way they
are always going to fit.
 Running shoes are used for running, so they
need to be more roomy than a regular shoe.
Why? Remember the force of heel strike…
each foot does this 500 TIMES EACH MILE, so
your feet tend to spread out.
3 KEYS to a GOOD FIT
1) You should have about a thumb's width of
room at the toe. If you can't wiggle your toes,
then move up to the next size.
2) The shoe should hold your foot securely
around the midfoot (arch and instep) and at the
heel, with little or no slipping.
3) The shape of the shoe should match the shape
of the foot (more on this later).
Bigger is Better
 If you aren't sure of which size to buy, it's nearly always better
to choose the larger size because much more can be done to
fine-tune the fit:
 change to a thicker sock like Thorlo
 add a replacement insole; these are thicker and more durable
than standard insoles
 adjust the lacing to snug up the fit (lace lock, for example)
 If a shoe is too small, there's not much you can do. Since
running shoes don't stretch, the only option is to try a thinner
sock.
Running Biomechanics
 Gait Cycle - the progression of the foot as it heel
strikes (phase #1)
 Heel Strike
Running is a "High Impact" activity, meaning that
at some point, both feet are off the ground. How
much impact? Wanna Guess? A runner comes
down with 3.5 times his/her body weight. What
does our body need to do with that shock?
Absorb it! Cushion it! Dissipate it! Disperse it! If
we don't, it travels back up the legs, causing
injury.
Running Biomechanics
 rolls to midfoot (phase #2)

Midfoot phase
What do we have in the midfoot? (The arch!)
3 Types of Arches:

Flat - flat arches are extremely flexible and require a great deal of
control

Medium - neutral arch is ideal and requires a degree of stability

High - high arches are extremely rigid and inflexible and require
little if any control
Running Biomechanics
 then to toe-off (phase #3)

Toe-off
The toe-off tells us what type of
pronator a runner is. Most runners will
look at the bottom of their running
shoes and conclude that they wear out
the outside of their shoe because the
outside heel is worn. From this, they
may conclude that they need a
cushioning shoe. Most are wrong!
Everybody wears out the outside heel.
It's the wear pattern at "toe off" that will
determine your rate of pronation, and
therefore the type of shoe you should
be running in.
2 Styles of Shoe Shape

Volume: (high or low)
- some shoes have
more space at the midfoot to accommodate a
high instep. Others
have less room than
average and are a
better match for a low
instep.
Shoe Volume and….
 Curve: some people
have feet almost as
straight as a ski; others
are almost as curved as
a banana. Shoes vary
nearly as much. The
amount of curve is
usually linked to running
mechanics.
2 FACTORS!
 Do you have a flat, neutral or high arch?
 Is your foot straight or curved?
 These two factors have to do with the amount of
pronation taking place…
Pronation
 Pronation is the natural, inward roll of the foot;
 Pronation begins when the heel contacts the
ground, the foot then rolls inward to absorb shock
and transfer weight to the ball of the foot as it
prepares to push off. It is a natural and necessary
motion for running and walking.
Ion,
 They’re three types of runners: the overpronator,
the neutral pronator, and the supinator (also
underpronator).
Motion Control: Low Arch
 Motion control: excessive
over-pronators, in addition to
low arches, generally have
rather straight feet. Motion
control shoes have the same
straight shape.
Motion Control: Overpronator
 Overpronator - The excessive inward roll of the foot. A
flat foot absorbs a lot of shock. It's very flexible and
needs support. Motion control shoes work best for
overpronators.
 Straight - shape found in motion control shoes built for
overpronators
Stability: Medium Arch
 Stability: the majority of
people have some curve in
their feet; that's why the
semi- curved shape of a
classic stability shoe like the
Asics GT-2000 series fits so
many people well.
Stability: Neutral
 Neutral pronator - The foot pronates naturally. Mild
pronators disperse shock effectively. A medium arch
absorbs shock moderately. Stability shoes work best for
the neutral pronator.
 Semi-curved - shape found in stability shoes built for
mild pronators
Cushion: High Arch
 Cushion: efficient/
underpronators tend to have
feet more curved than
average to go with their high
arches. Shoes like the
adidas Response Trail are
also more curved than
average.
Cushion: Supinator
 Underpronator (Supinator) - the lack of sufficient
inward motion of the foot. A high arch absorbs less
shock. Cushioning shoes that are highly flexible are
best for the underpronator. Only a small population
truly underpronates.
 Curved - shape found in cushioned shoes built for
underpronators
If you say:
 I can't close my shoe laces…
It Means This:
 Your shoe doesn't have enough volume. That means
you need a wider shoe.
If you say this:
 My shoe laces close up all the way…
It means this:
 Your shoe has too much volume, and you need a shoe
that is narrow.
If you say this:
 My big toes are squished….
It means this:
 Your shoe is too straight
(curved foot runs into shoe) sometimes causing
blisters, irritation on the big toe side.
If you say this:
 My small toes are squished…
It means this:
 Your shoe is too curved
(curved shoe runs into foot) and you need a straight
lasted shoe.
If you say this:
 Tight at ball of foot, foot falls asleep, circulation
reduced
It means this:
 Shoe is too small, size up. Women especially get their
running shoes too small.
Shoes for different weight
 Average male weight 165-180 - anything below range
is considered a lightweight runner, anything above is
considered a heavy weight runner
 Average women's weight 125-150 - anything below
range is considered a lightweight runner , anything
above is a heavy weight runner
Shoe Construction
 Last thing to know is the construction:
There are three types:
Board, Combination & Slip
Board Construction
1. Board - Cardboard piece in shape of footbed
that adds stability
 Purpose of a board last: Provide full length support
(not common in running shoes) (Anyone have a bad
back? Anyone ever put plywood under a mattress or
know someone who does? Why? To provide support.
Same concept as Board/Combination lasts)
Combination Construction
 Combination - Half board in heel, half soft, moccasin
like construction in forefoot
 Purpose of combination last: Provides stability in the
heel and support in the midfoot
Slip Construction
 Slip - entire footbed is built like a moccassin to promote
flexibility
 Purpose of slip last: Provides flexibility