Biomechanical Aspects Of Sport Shoe And Surface Design

Question 1

In which plane is rear foot motion monitored?

Answer 1

2D frontal plane

From behind

Question 2

How is rear foot motion monitored?

Answer 2

Place markers to create segment at top & bottom of calf and top & base of heel to track relative angle between foot and shank
Clarify which leg you’re monitoring

Question 3

In 2D approach of rear foot monitoring, we look at the relationship between …………. & ………….

Answer 3

Inversion & eversion

Question 4

In 3D approach of rear foot monitoring, we look at the relationship between …………. & ………….

Answer 4

Pronation and supination

Question 5

What is excessive eversion classified as?

Answer 5

12 degrees

Question 6

Considerations when classifying max eversion?

Answer 6

12 degrees Won’t be true for all athletes
Could have an athlete that everts more then 12 but doesn’t get injured
Could have an athlete that everts less than 12 but still gets injured

Question 7

Describe rear foot movement graph

Answer 7

Y axis = rear foot angle
X axis = time

anything above 0 is inversion
Below 0 shows movement towards eversion
Maximum eversion is the max rear foot angle.

Question 8

Static assessment definition

Answer 8

The use of visual assessments only - running shops use this.

Question 9

Shoe stability (motion control) definition?
How is it quantified?

Answer 9

Ability of shoe to resist excessive (12 deg) or unwanted motion of the foot and ankle,
Quantified by measuring rear foot movement

Question 10

Eversion definition

Answer 10

A movement in which the plantar surface of the foot rotates away from mid line of the body (little toe up)

Question 11

Inversion definition

Answer 11

A movement in which the plantar surface of the foot rotates towards the midline of the body (big toe up)

Question 12

Shoe design characteristics:

Describe heel flare

Answer 12

When a lateral or medial border is built on the heel of the shoe to increase shoe stability and therefore reduce rear foot movement

Question 13

Results of increased medial heel flare

Author

Answer 13

Reduced magnitude of eversion during stance
= reduced rear foot movement

Clarke et al., 1983 or Nigg & Morlock, 1987

Question 14

Result of lateral heel flare

Authors

Answer 14

Reduced leverage length
= reduced rear foot movement
(Shortened length of movement arm between axis of rotation and point where force is being applied)

Nigg & Morlock, 1987

Question 15

Issue with heel flares

Answer 15

Could change the shape and width of parts of the shoe which could minimise some of the cushioning properties that the shoe provides

Question 16

Describe medial post of shoe

Answer 16

Part of the midsole that’s firmer than rest of midsole

E.g. Plastic moulding - a butterfly effect on base of shoe that prevents rocking action

Question 17

What determines how much stability the medial post gives a shoe

Answer 17

Shape and size of post

Question 18

In what type of shoe is a medial post never found in?

Answer 18

Cushioned

Question 19

Disadvantage of shoes with medial post?

Answer 19

Adds weight to shoe

Question 20

Which parts of foot does a medial post stabilise and what does this prevent?

Answer 20

Midsole, rear foot

Arch pronation

Question 21

Authors that found that shoes with a high density medial post reduced rear foot movement?

Answer 21

Cheung & Ng, 2007

Question 22

Describe orthotic devices

Answer 22

In other words - an insole

Question 23

What did Clarke et al., 1983 investigate in relation to orthotic devices?

Answer 23

The influence of orthotic devices on rear foot movement

Question 24

Findings of Clarke et al., 1983 (2)

Answer 24

Eversion occurs without orthotic device support

With orthotic device, more alignment between shank and heel to reduce angle of eversion and rear foot movement

Question 25

In which circumstances should biomechanics and podiatry be used to assess the effects of orthotics on rear foot movement?

Answer 25

Podiatry - static assessments in an unloaded (not standing) position to decide whether insole is needed Biomechanics - investigate the effects of orthotic device on running, walking or when static

Question 26

Disadvantage of orthotics?

Answer 26

To much cushioning adds instability

Question 27

Orthotic devices: | Findings of Mundermann et al., 2003?

Answer 27

Orthotic devices reduce peak eversion and eversion velocity which lowers injury risk

Question 28

Orthotic devices: | Findings of Nigg et al., 1998

Answer 28

Orthotic devices have no influence on movement - no change in eversion characteristics

Question 29

Orthotic devices: | Findings of Gross et al., 1991

Answer 29

Orthotic devices helped 75% of distance runners | 25% showed worse symptoms, no change or picked up an injury from the device

Question 30

``` Summary or shoe properties: Medial posting Medial properties Heel flare Orthotic devices ```

Answer 30

Medial posting - some Evidence of increase stability; Cheung & Ng, 2007 Medial properties - high density materials can increase stability; Cheung & Ng, 2007 Heel flare - medial and lateral flare can be influential in reducing rear foot eversion and therefore rear foot movement; Nigg & Morlock, 1987 Orthotic devices - some evidence of increased stability; Gross et al., 1991

Question 31

Describe Surface cushioning

Answer 31

The ability of a surface to reduce peak impact forces by providing cushioning athlete during ground contact

Question 32

Typical ground reaction force -time history?

Answer 32

Y axis = vertical ground reaction force (1-2BW) X axis = time (ms) Initial peak is impact peak, second peak is active peak

Question 33

What is the duration of impact phase for a typical heel toe runner?

Answer 33

Approx 50milliseconds

Question 34

What does the steepness of the curve in a ground reaction force - time history show?

Answer 34

Rate of loading When curve is really steep, loading rate is high When curve is flatter, loading rate is low

Question 35

What information regarding shoe and surface design does a ground reaction force-time history provide?

Answer 35

Cushioning

Question 36

What type of force is linked with injury risk?

Answer 36

impact force

Question 37

With an increase in shoe cushioning, what is known to be reduced?

Answer 37

Loading rates (steepness of curve)

Question 38

What effect does barefoot running have on ground reaction force-time histories.

Answer 38

Steeper curve

Question 39

How does barefoot running influence foot strike? | And what does this depend on?

Answer 39

See more of a forefoot or mid foot strike | Depending on speed

Question 40

Why is a forefoot or mid strike observed in barefoot running? Author who found this?

Answer 40

Foot is presented flatter to ground to compensate for higher impact at the heel Dixon et al., 2005

Question 41

How can friction be varied in hard tennis courts?

Answer 41

Very amount of sand put into acrylic paint that coats the court. More sand = more friction

Question 42

Influence of temperature on surface design

Answer 42

Very high temperatures can make court sticky = more friction

Question 43

How to test surface properties?

Answer 43

Use a portable skid resistance tester. (Industry standard) Depending on resistance of surface, foot will continue to swing upwards after ground contact. Distance above ground is then measured

Question 44

Regarding player - shoe - surface relationship, when can an inversion injury occur? (2)

Answer 44

(1) lack of kinaesthetic awareness and foot placement | (2) when there's a sudden change in shoe - surface interaction

Question 45

What is the coefficient of friction influenced by?

Answer 45

Shoe - surface variation

Question 46

What did Gheluwe & Deporte, 1992 find?

Answer 46

That the surface is more influential on stability than the shoe

Question 47

In shoes, what's the relationship between increased performance and injury risk? Example

Answer 47

Contradictory relationship. E.g. Football boots. Early 1900's - hard leather, lace up above ankle, heavy boots (1kg) with HIGH STABILITY 1954 - 'Adi' (Adolf) Dassler made LIGHT (360g), below ankle laced boots Since then, the game has got faster, more skilful and dynamic. An attitude swing to boost performance with less emphasis on injury

Question 48

What did Bentley et al., 2010 find in regard to football shoes?

Answer 48

Blades lead to higher plantar pressure and injury risk

Question 49

What did Henning, 2006 find in relation to the injury-performance relationship?

Answer 49

Injury prevention ranked low on priority list

Question 50

Typical characteristics of shoes highlighted in advertising (5)

Answer 50

``` Shock absorbing/ cushioning Motion control Traction Weight Comfort ```