16_18- Footwear Flashcards by Marco DiFederico

What changed in the 70s which made running shoes start to become much better?

People started running to become fit/to improve performance in other sports

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What are the different functions of the outsole, midsole, and heel counter in a running shoe?

Outsole: interface bw ground and shoe

Midsole: provides cushioning and supprt

Heel counter: provides stability and motion control

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Why does the posterolateral portion of a running shoe tend to wear out the quickest while most of the shoe remains untouched?

Avg forward velocity at heel contact is 1m/s, and most people are heel-strikers.

After heel strike, shoe is not moving until just before foot is lifted off the ground

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Your patient has a strike index of 8%. This would indicatethat the patient is a:
A. Forefoot striker
B. Midfoot striker
C. Rearfoot striker

Rearfoot striker - SI is measure of point of initial contact as a percent of the length of the shoe

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Individuals with pes planus tend to have the most pressure in the (heel/forefoot) while individuals with pes cavus tend to have the most pressure in the (heel/forefoot) during gait.

Forefoot; heel

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What are the risks of having too much cushioning in a running shoe? Too little?

Too much: shoe will bottom out

Too little: excessive shock to leg

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Where should a shoe bend relative to the structures of the foot?

Behind the metatarsals

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What is the major effect of a shoe’s weight on function?

Every 100g increases energy expenditure by 1%

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Which factors help reduce over-pronation?
A. Stiff heel counter
B. Increased heel height
C. Increased medial midsole stiffness
D. Straight last

All of the above

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How is the subtalar joint affected differently on heel contact depending on if you’re wearing running shoes vs. barefoot? What is the result?

Barefoot: ground reaction forces go right through subtalar joint axis, so no rotation forces generated

Running shoes: larger shoe width creates moment arm for GRF on subtalar joint

Result: more likely to over-pronate with running shoes

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Why are anterior shin splints more likely when wearing running shoes vs running barefoot?

The heel of running shoes creates a larger moment arm for plantarflexion, which means tib ant needs to resist more force

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Early running shoes caused problems such as overpronation and increased plantarflexion moments. How is this resolved in newer running shoes?

Double-density sole + rounded lateral heel

Lateral part is softer to absorb extra pronation GRF generated at heel strike

Medial part is harder to resist pronation

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True or false: the vast majority of runners who over pronate develop overuse injuries

False - 40-50% of runners with excessive pronation do NOT have overuse injuries

BUT individuals with injuries have an avg of 2-4degrees of increased pronation compared to non-injured runners

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The transfer of pronation into tibial pronation has been found to be the best predictor of overuse injuries. Which is more likely to cause injury:

a) 20 degree angle of the axis of rotation between talus and tibia
b) 60 degree angle of the axis of rotation between talus and tibia

B - will lead to 13 degrees if tibial rotation (vs only 3 degrees if angle is 20deg)

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What is the “last” of the running shoe?

What kind of last is ideal for oversupinators?

Overpronators?

Line from the middle of the heel to the middle of the big toe

Overpronators: straight
Oversupinators: curved

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The most common last configuration in modern running shoes is:
A. Board last
B. Combination last
C. Strobel board last
D. Slip last

C - board made of cloth or thin sheet of EVA glued to midsole

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Which 4 tests should you do on a patient’s shoe to check for motion control?

Torsional rigidity (dish-rag)
Heel counter rigidity (pinch test)
Flexion stability (fold test)
Upper stability (shelf test)

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At what point in the shoe should a fold in the flexion stability test?

Behind met heads

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What is the role of heel counter rigidity in running

Proprioception (NOT buttressing)

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What is the difference between a positive and negative heel drop? What are their advantages?

Positive heel drop = heel height > toe height. Found in most running shoes to reduce over-pronation b/c is dorsiflexes the hallux, encouraging subtalar joint supination through the Windlass effect
Negative heel drop = heel height < toe height. Helps encourage midfoot strike rather than heel-strike

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An elderly patient asks you for running shoe recommendations. They are choosing between EVA and polyurethane midsole material. Which would you recommend? What are the benefits and drawbacks?

EVA - very light and provides responsive cushioning

Con:

takes 24 hours to decompress and regain shock absorption after wearing - should recommend buying 2 pairs and switching between them each day
not as durable as polyurethane

Your patient is an over-pronator. Which drop would be more likely to match their foottype?

A. 8mm
B. 0mm

Almost all shoes today have an outer sole made of a combination of _________ ________ and ____________ _____________ ______________

Blown rubber (least durable)
Carbon impregnated rubber (usually at back of heel - much more durable)

In general, you should always recommend a sole with the greatest surface area. Why? What is the exception?

Better stability to roation about long axis of shoe

Exception: older people - may increase risk of tripping

What kind of shoes should you recommend to an individual with hallux rigidus?

Four finger rocker

What kind of shoes should you recommend to an individual with mortons neuroma?

Wide forefoot, narrow heel

Trail running shoes should have large ________ and a _________ _________ to prevent rock bruises

Lugs (sole made of rubber with deep indentations/grooves to provide added grip); gait plate

A patient has reported having pain across the top of their feet. How should they lace their shoes to avoid this?

Lace to the point where the pain begins(normal lacing) then skip the cross-over in the region where there is pain. Then go back to normal lacing. Because you don't have the laces crossingover in the area of pain - it shouldn't beirritated anymore

How should shoes be laced for individuals with high arched feet?

Going across-up the whole way on both sides

A patient complains that their heel keeps slipping out of their shoe and they've been getting blisters. How can you help them?

Lace shoes up to second-last eyelet normally. Create two eyelets by lacing up and not across the last hole, then cross through the loop made by the last eyelet.

A patient has been experiencing a lot of pain in their big toe and wonders if they can do anything different to reduce the pain. What do you recommend?

Put the lace in the top left, and straight down to the bottom right and then continuing the lace up. It will pick up the end of the shoe and won't irritate the toe anymore.

What are 4 important features of a tennis shoe which are different from running shoes?

1. Lateral stability (due to changing direction side-to-tide) 2. Torsional flexibility 3. Cushioning (especially in toe area) 4. Traction control

When a study was done comparing injury rates among subjects wearing different shoetypes, the greatest injury rate was seen in those wearing: A. Neutral shoes B. Partial minimalist shoes C. Full minimalist shoes

B (therefore need to be careful about prescribing minimalist shoes to patients)

What are 2 differences with women's running shoes?

1. Softer midsole and lighter because women generally weight less so don't have the same degree of impact 2. Wider forefoot and narrower heel

Your patient is an over-pronator. Regarding lacing, what would you recommend? A. Keep the laces loose by use all 7 eyelets B. Keep the shoes tight and use all 7 eyelets C. Keep the shoes loose but only use 5 eyelets D. Keep the shoes tight but only use 5 eyelets

B (also reduces peak pressure on heel)

What effect does increased midsole hardness have on impact peak, energy loss, and contact time?

Reduce impact peak Minimize energy loss Increase contact time

``` Which midsole material has better energy return? A. EVA B. Sprayed rubber C. Polyurethane D. Tire rubber ```

A (which may translate into improved running economy)

True or false: running economy has been found to increase with minimalist footwear

True - thought to be due to greater cross-sectional area and stiffness of Achilles tendon

What is the main concern wrt training in minimalist shoes?

ncreased risk of injury, especially to shin, forefoot (stress fracture) and calf

True or false: heel flare has been found to increase the risk of over-pronation in runners

False - no sig dif in tibiocalcaneal and ankle kinematics between heel flare conditions

Which type of heel cup is recommended for heel fat pad atrophy? A. Rubber B. Plastic

B - improved internal shock absorbtion because it squishes the heel pad, causing increased thickness

Which type of heel cup is recommended for heel inflammation? A. Rubber B. Plastic

A - increased external shock absorption

True or false: according to the latest research, there is no significant difference of overall injury risk among different heel-toe drops

TrueTrue

Minimalist uppers were found to cause higher peak pressure in all areas of the foot except ___________

Midfoot region

What is the main role of the upper of a shoe?

Improved coupling of foot with sole

Roy and Steganyshyn had 3 hypothesis about shoe longitudinal bending stiffness, that is would be inversely correlated to: 1. Gross metabolic cost 2. Work at MTP joint 3. Total intensity of muscular activity of the lower limbs Which turned out to be correct?

None of them! No impact on any of these metrics.

What factor is most important to take into consideration when determining ideal shoe stiffness to maximize running economy?

Runner's mass (heavier subjects should have stiffer shoes)

True or false: Running in lighter shoes improves running economy compared to running in heavyshoes.

True

True or false: minimalist shoes show greater running economy compared to conventional shoes because they weigh less

False - greater running economy even when weight is accounted for (probably because of forefoot running style)

True or false: Benno Nigg believes that nobody really knows that the Vaporfly is doing, but it is doing something.

True - there are several theories (eg. lighter running shoes, stiffer midsole which increases moment arm) but these have not been proven