Controllable Factors 2 Flashcards
Criteria for selecting running shoes
Performance Protection Comfort Durability Weight Price Taste / Fashion
Essential Charecotristics of a running shoe
Attenuation of single/multiple impact forces Preservation of foot stability Adequate friction/traction Provision of different foot strike type Heat disssipation Comfort
Uppers Structure of a shoe
a compound structure (foam layer-nylon-cotton weave).
Midsoles and Wedges
the shock absorption parts of the shoe, made
from closed-cells polymeric foam (EVA) which contain gas or liquid.
Durability: –30% after 500 miles.
Outsoles:
durable and abrasion-resistant polyurethane rubbers. Treading
increases the traction, especially under wet conditions.
Insole board
A fibre-board that provides the rigid base for the rest of the
shoe (
Insole
Heel Counter
Inserts
Insole: This part (polyethylene foam with fabric cover) contributes to the reduction of impact
forces, perspiration absorption and comfort.
Heel counter: provides rear-foot stability and claimed to prevent excessive pronation (hard
or high heel tabs may cause tendon inflammation).
Inserts: These help to reduce impact and increase rear-foot stability.
What are impact forces related to?
Stress fractures and achillies bursitis
Impact force variables?
peak vertical force time to peak vertical force peak loading rate time to peak loading rate.
Which type of runner has greater impact forces?
Vertical impact forces are greater for heel than mid foot and forefoot strikers.
Energy absorption in shoe
60% midsole-wedge, 20% outsole, 10% insole, 3% insole board and 2% sock.
Heel sole shapes available
Flared, neutral, rounded
Differences in bare foot running to with shoes?
barefoot tends to lead to different running techniques than shod (i.e., initial contact is
typically made on the forefoot rather than the heel) but this
in itself could lead to injury because of increased loading on
the calf muscles
Why is barefoot running technique beneficial in running?
Increased use of the stretch shortening cycle
What is compliance?
The opposite of stiffness
Low compliance = high risk of injury
High compliance = low performance
What is resilience?
The amount of energy returned
as a percentage of the amount
of energy absorbed at impact
Impact attenuation?
Measurement of reduction of impact forces
Running on softer surfaces?
running on surfaces such as sand, grass and trails requires greater metabolic energy expenditure than running on smooth, flat, hard surfaces
Why running on sand has greater energy cost?
because of a reduction in elastic energy potentiation, caused partly by an increase in contact time (and thus a longer
delay between the eccentric and concentric actions of the lower limb muscles).
Concrete/ asphalt surface
High resilience - good traction
Stiff - low compliance
Outdoor surfaces
Good traction and high resilience
Synthetic turf
high resilience, low injury risk, good for correct playing characteristics
Suggested running surfaces
Grass, dirt paths and wood chips
