Lecture 1 - protective equipment, what makes the perfect fit? Flashcards
what factors are important in the prevention of athletic injuries?
- design
- to prevent injury
- to protect injured parts from further injury. - proper fit
- proper selection
protective equipment
- simple to fit and maintain
- be durable and reliable
- not be extremely expensive
- minimal functional interference (they have to be able to do their job while wearing it)
what are the 4 principles of protective equipment?
- deflection
- dissipation
- deformation
- absorption
deflection
- a turning aside or off course
what properties are important in deflecting force away from the body?
- hard
- rounded
-smooth - ridges
dissipation
to cause to spread thin or scatter and gradually vanish
- disperse focal force over a larger surface
- layers
- various materials
deformation
alteration of form or shape
- change in shape or structure (cantilever pads)
- may blow apart @ high force (bike helmet)
what is a cantilever pad?
a metal piece in football pads that basically allows for when force comes down it will bend and then make the force go outwards instead of straight down on you
absorption
- to receive without recoil or echo
materials: - felt
-foam
(open or closed cell) - air
-fluid
increased density
greater resistance @ high force (used more for protection)
decreased density
more absorption @ lower force
- like a sponge
-better absorption at lower forces
- these are more for comfort.
absorption materials: felt
- made from matted wool fibers
-less tendency to shift or move over skin
-absorbs fluids (sweat, blood, etc) - not very resilient
-must be replaced daily
absorption materials
- felt
- foam
open cell foam
- like sponge
- low resilience- doesn’t bounce back fast
- used to pad bony prominences
- used to protect skin under hard edges of protective equipment
who might be people that would use open foam materials?
athletes in contact sports who might be hit multiple times usually wear this type of equipment.
closed cell foam
- used primarily for protection (air can not pass from one to another)
- high resilience-material rebounds and returns to its original shape quickly
where would closed cell foam most likely be found?
- inside of football helmets
- it bounces back right away
fitting equipments
- mold to body part
- allow function
- allow for quick removal in emergencies
fitting helmets
- you want to have wet hair
- 1-2 finger widths above eye brow
-covers occiput and entire skull - mask 2-3 finger width from nose (good vision and for protecting your face)
- snug to chin (2 vs 4 point)
what can fit be altered by?
- temperature
- hair length
- deterioration of internal padding
- loss of air (air bladder helmet)
why is a good fit important?
- protection
- ability to play
- prevent injuries
shoulder pads - general sizing
- inner padding covers shoulders and cups deltoid
- neck unrestrictive
- lacing sung but unrestrictive
modifying equipment
- any modifications should be done according to the manufactures specification and should not alter the fit of the original equipment
- modification should not increase stress or damage to original material (no drilling, cutting, slicing!)
what do you need to think about in sport specific equipment analysis
- biomechanics of body parts
-individual activity level - specific protection/performance demands
what is equipment protecting against?
- people (high mass/low velocity. slow compared to throwing a baseball for example
- projectiles (low mass/high velocity
what is a football helmet
- high mass/ low velocity
- hard smooth outer shell with absorbing inner liners (air/closed cell)
(plastic/polycarbonate) - will have different mask depending on position
football shoulder pads
- protect shoulders and limit force to lateral acromion
- shell of hard, smooth plastic (for deflection)
- layers of soft padding under outer shell - held away from AC like a cantilever
- dissipation
- deformation
- absorption
hockey helmet
- high velocity/low mass (puck ) and low velocity/ high mass (player)
- hard shell with high density inner lining
-open and close cell foam combination
-full cage or half visor
goalie mask
- high velocity.low mass (puck) and minimal low velocity/high mass
- hard shell with ridges (deflection)
- open and close cell foam combination (absorption)
hockey shoulder pads
- designed with overlapping cup to protect clavicle and deltoid from lateral contact (dissipation)
- chest portion usually felt or nylon and foam (absorption)
hockey and baseball shin pads
- molded plastic to cover knees and shins (foot for baseball) (deflection/deformation)
- some articulation around knee (allows greater freedom)
- layer4ed nylon/foam or felt lining (absorption)
baseball helmet
- low mass/high velocity (pitch)
- hard round plastic (deflection)
- ear protection
- designed to protect from focal impact (dissipate and absorb force)
- up to batter to turn face away (some little leagues use face shield)
baseball chest protector
- soft foam - should be form fitting with no gaps
-heart guard - extra layers
catchers masks
- protection from ball and bat splinters
conventional
- poor vision and jaw padding
- minimal ridges
hockey style
- better vision and protection (deflection)
- problems
- hot - wearing in hot weather
- heavy
-hard to flip off
lacrosse helmet
- similar protective principles as hockey helmet
- high velocity/low mass and low velocity / high mass
- sits off crown of head
- mask farther from face for increased visibility
- visor peak for sun
biking/inline skating helmet
- outer designed for one massive impact at high velocity
- deformation (hopefully it will break upon impact)
- foam inner lining (absorption/comfort)
- peaked front and back to protect face and occiput
bike/inline skating wrist gaurds
- rigid plastic over open cell foam
- deflects impact of FOOSH (absorption)
FOOSH
fall
on
outstretched
hand
two major shapes of a shoe
- straight lasted shoe
(pretty much the straight line down the middle of it) - curved lasted shoe
LASTS
- external last (shape) is the form on which the shoe is constructed
- internal last (construction) is there interference between the foot and the midsole
slip last
gives the foot a ton of flexibility (i.e. for ballet, bare-foot running trail shoes, climbing)
flat feet
- put them on a board arch
last shape-internal
- slip lasting
- board lasting
slip lasting
- solid line of stitching down center of shoe
-increased flexibility - neutral or any kind of shoe that require flexibility
board lasting
- solid board stitched to upper of shoe
-increased torsional resistance to pronation - better interface for orthotics
anatomy of the shoe
- upper
- midsole
- outsole
- heel counter
upper part of shoe
- all components above the mid sole
- nylon, mesh leather, synthetics
- contains mid foot control technologies
- conforms to bony abnormalities
- whole point of the upper part of the shoe is to either conform to the foot or protect the foot
midsole of the shoe
- between upper and outsole
- shock absorption vs. motion control/controlling motion
-densities depend on sport and foot type - absence of midsole in some shoes that require better “feel” or ball control
what is the midsole material?
- polyurethane, EVA, and compressed EVA
- pu contains heavier runners (a little bit denser, this is the controller)
- tapered from heel to toe, with thickest portion under the heel
- EVA is lighter - when compressed, it has increased durability (shock absorber)
outsole
- protective layer on bottom
- protection, durability, flexibility, traction
-use of different rubbers and other materials specific to sport
heel counter
- the stiff material at the back of the shoe built to resist motion in the ankle. more pronation needs stiffer heel counter.
- there to hold the back of your foot on the base of the shoe.
- squeeze to see how firm
- at the top of the heel counter is an ankle collar which is intended to protect/cushion the ankle and achilles tendon
how do you fix a too wide shoe?
- can be filled with felt or a heel cap
footwear fit
- to test width, place full weight on shoe. pushing thumbs together over top of shoe should produce a ripple.
- the toe box end of the shoe should be 1-1.5cm from end of longest toe
how do you tell if a shoe fits right when pressing down on it?
- if there are too many ripples the shoe is too wide.
-2. if it does not produce a ripple at all it is too tight
- if there are too many ripples the shoe is too wide.
what are shoe (last) classified as?
- straight
- curved
- semi-curved
rigid (cavus) foot
- curved last with sufficient cushioning
- someone with a rigid foot means they have a high arch
mobile (flat) foot
- straight last
fitting heel to forefoot height
- important with rigid cavus foot or forefoot pain.
- too high a heel will increase force on forefoot, which is not designed to absorb extra energy
- lower heel will allow energy to be taken throughout full foot.
- look for shoe with only a slight difference in height
- think of an areo bar
neutral cushioning - neutral foot/high arch
- single density midsole
- thermoplastic heel counter
-mild torsional rigidity - proprietary cushioning (EVA)
- slip and curve lasted
- used for “normal”, neutral asymptomatic population
stability shoes - mild over-prontors
- thermosplastic heel counter
- double density midsole-PU
- moderate/extreme torsional rigidity (will stop the rotation)
- midfoot control
- curved last
- board lasted
- think of a skore bar
motion control shoe - severe over-pronators/flat feet
- thermosplastic heel counter
- triple density midsole
- medial and laterally posted
- extreme torsional rigidity
- midf oot control
- board lasted
- straight lasted
- kinda like a tix bar
- will be very hard to bend
