Paul Thawley MSc Choosing the Correct Shoe

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Paul Thawley MScChoosing the Correct Shoe
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Definitions

• Last The template or model upon which the shoe
  is built. Different manufacturers use different
  lasts.

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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 airinjected 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.

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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.

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Definitions (cont.)

• 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.

• 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 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.

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Definitions (cont.)

• Counter A rigid piece surrounding the heel that
  provides some stability.

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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.

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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.

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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).

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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.

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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.

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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

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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.

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2 Styles of Shoe Shape

• Volume (high or low) - some shoes have more
  space at the mid-foot to accommodate a high
  instep. Others have less room than average and
  are a better match for a low instep.

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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.

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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

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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,
• Theyre three types of runners the overpronator,
  the neutral pronator, and the supinator (also
  underpronator).

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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.

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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

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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.

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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

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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.

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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

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If you say

• I can't close my shoe laces

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It Means This

• Your shoe doesn't have enough volume. That means
  you need a wider shoe.

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If you say this

• My shoe laces close up all the way

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It means this

• Your shoe has too much volume, and you need a
  shoe that is narrow.

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If you say this

• My big toes are squished.

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It means this

• Your shoe is too straight  (curved foot runs
  into shoe) sometimes causing blisters, irritation
  on the big toe side.

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If you say this

• My small toes are squished

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It means this

• Your shoe is too curved  (curved shoe runs into
  foot) and you need a straight lasted shoe.

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If you say this

• Tight at ball of foot, foot falls asleep,
  circulation reduced

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It means this

• Shoe is too small, size up. Women especially get
  their running shoes too small.

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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

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Shoe Construction

• Last thing to know is the construction There
  are three typesBoard, Combination Slip

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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)

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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

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Slip Construction

• Slip - entire footbed is built like a moccassin
  to promote flexibility
• Purpose of slip last Provides flexibility