Lec 2 Protective Equipment PDF

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Protective Equipment Athletic Equipment  Many factors are important in the prevention of athletic injuries  Design- prevent and protect o To prevent injury (primary) o To protect injured parts from further injury (secondary)  Proper fit  Proper selection Protective Equipment  Practicality dictates that protective equipment should be: o Simple to fit and maintain o Be durable and reliable o Not be extremely expensive o Minimal functional interference  4 principles: 1. Deflection 2. Dissipation 3. Deformation 4. Absorption 1.

Deflection  A turning aside or off course  Which properties are important in deflecting force away from the body  Goalie mask & football helmet o Round- won’t hit square on, glide off o Hard o Smooth o Goalie mask has ridges to deflect pucks o Football helmet doesn’t- will increase torque on neck

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Dissipation  To cause to spread thin or scatter and gradually vanish  Disperse focal force over a larger surface  Shoulder pads o LARGE surface pad- disperse force over pad not joint; protect small AC joint o 3 layers made of various materials (harder, high density foam, lighter density foam) o By time force goes through, spreads out and dissipates through these materials

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Deformation  Alteration of form or shape; change in shape or structure o Cantilever pads in football- sit up higher on top of someone’s shoulder o When pressure comes down, downward force goes outward; puts pressure to blow out instead of down on shoulder o Cantilevered pads are bulkier and disperse force into the pads rather than the shoulders o These pads are designed for players that block and tackle  May blow apart @ high force o Ex. Bike helmet o Deforms, blows apart and absorbs the force o Should replace helmet after a fall or drop, can cause cracks that will hinder protection

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Absorption  To receive without recoil or echo (ex. bowling ball on mattress)  Increased density = greater resistance @ high force *  Decreased density = more absorption @ lower force *  Materials:

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Felt o Made from matted wool fibers o Less tendency to shift or move over the skin (less slip and slide) o Problem: absorbs fluid (sweat, blood, etc.), gets heavy, doesn’t dry quickly o Must be replaced daily! o Seen is the tongues of skates Open Cell Foam o Like sponge o Low resilience- doesn’t bounce back o Comfortable, layer closest to skin o Used to pad bony prominences (elbow, forehead) o Used to protect skin under hard edges of protective equipment; comfort not protection o Decreased density = more absorption @ lower force (shoulder pad sitting on shoulder for whole game) Closed Cell Foam o Main part of protection o Used primarily for protection (air can’t pass from one to another; cant leave bubble) o High resilience- material rebounds and returns to its original shape quickly o Made for multiple fast impacts  Offers less cushioning at low levels of impact  Not as comfortable close to the skin  Offer a lot of resistance at high force o Bubbles of trapped air in the foam are complete bubbles, with cell walls all around, like a million balloons all stuck together. This kind of foam gets most of its properties from the air trapped inside the bubbles. When the foam is compressed, say when you’re walking on an insole or when you land on your elbow pad, the air inside the bubbles is compressed, and the return force is caused by the decompression of the air. o Increased density = greater resistance @ high force Air Fluid

Fitting Equipment  “firm but comfortable”  Mold to body part  Allow function; nothing too big or bulky  Allow for quick removal in emergencies Fitting Helmets  Wet hair  1-2 finger widths above eyebrow (front)  Covers occiput (back) and entire skull  Mask 2-3 finger width from nose for good vision (incase helmet gets pushed back into your face)  Strap snug to chin (2 vs. 4 point) Why is a good fit important?  Protect head, face  Can block your vision, won’t be functional in what you’re doing Fit can be altered by (can make helmet loose):  Temperature  Hair length  Deterioration of internal padding (bad helmet)  Loss of air (air bladder helmet- more you hit, lose the air Shoulder Pads- General Sizing  Inner padding covers shoulders and cups deltoid, big piece on top of AC  Neck unrestrictive

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Lacing snug but unrestrictive

Modifying Equipment  Any modifications should be done according to the manufacturer’s specification and should not alter the fit of the original equipment  Modifications should not increase stress or damage to original material o No drilling, cutting, slicing  will weaken o Equipment should come with the necessary holes for additional equipment add ons Sport Specific Equipment Analysis Need to think about:  Biomechanics of body part  Individual activity level  Specific protection/performance demands o What are you trying to protect against? o People? High mass/low velocity o Projectiles? Low mass/high velocity Analysis: Things to Look At  Outer surface “shell” for deflection  Inner surface “liner” for absorption  Method of attachment (strap, belt, ties)  Sport Specific Design (hockey vs. football helmet)  Other considerations: fit, quality/certification, ventilation, temperature, wear- recertification? Football Helmet High mass/low velocity (made to protect from people)  Hard, smooth outer shell for deflection with absorbing inner liners (air/closed cell for high forces) o Plastic/polycarbonate  Will have different mask depending on position; some need more vision  2 or 4 point chin strap- limits forward/backward tilting o The wider the straps, the more it stops your head from rotating o More contact sport will want wide 4 chin strap o Single chin strap- helmet rotates Shoulder Pads  Protect shoulders and limit force to lateral acromion (AC) o Shell of hard, smooth plastic for deflection o Layers of soft padding under outer shell- held away from AC like a cantilever  Dissipation  Deformation  Absorption o Different design than a hockey shoulder pad- different styles of hitting Hockey High velocity/low mass (puck) and low velocity/high mass (player) Helmet  Look different, weigh different, do a different job than football helmets; don’t hit with our heads in hockey  Hard shell with high density inner lining  Open and close cell foam combination  Full cage or ½ visor Goalie Mask  Mostly high velocity/low mass (puck)  For deflection  Hard shell with ridges  Open and closed cell foam combination- absorption

 When getting hit, chin doesn’t take blow, moves up the sides Shoulder Pads  Designed with overlapping cup to protect clavicle and deltoid from lateral contact o Dissipation o Protecting from force coming from the side  Chest portion usually felt or nylon and foam for absorption Neck Protectors- what are they there for?  Usually soft cloth with Kevlar or plastic insert  Purpose is to prevent throat lacerations (skate cuts), not for protection against getting hit by a puck o Minimal padding against low mass high velocity projectiles  Turn head, exposing throat instead of having chin down Hockey and Baseball Shin Pads; similar  Molded plastic to cover knees and shins (foot for baseball) o Deflection/deformation (hockey)  Hockey pads go around to the back of the leg more; more full contact sport o Some articulation around knee (baseball); allows greater freedom  Layered nylon/foam or felt lining for absorption Baseball Helmet Low mass/high velocity (pitch)  Hard round plastic for deflection  Soft foam for comfort, some closed cell foam  Ear protection  Designed to protect from focal impact o Dissipate and absorb force  Up to batter to turn face away (some little leagues use face shield) Chest Protector  Soft foam- should be form fitting with no gaps  Heart guard- extra layers Catcher’s Mask  Protection from ball and bat splinters  Conventional mask: o Poor vision and jaw padding  Minimal ridges  What does that mean to us?  Hockey Style (all around the head): o Better vision and protection  Deflection o Problems:  Hot- wearing in hot weather  Heavy  Hard to flip off Lacrosse Helmet (hockey-like)  High velocity/low mass and low velocity/high mass (person/stick)  Sits higher off crown of head  Mask farther from face for increased visibility (ball is heavier than puck)  Visor peaks for sun Shoulder Pads  Similar to hockey- decrease AC protection for an increased arm range available for stick work  Smaller than hockey & football pads Arm pads  Protect length of arm from slash Gloves

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Often open palm Decrease wrist padding for greater movement- means greater risk of injury

Bike/Inline Skating Helmet  Outer design for one massive impact at high velocity o Deformation  Foam inner lining o Absorption/comfort  Peaked front and back to protect face and occiput Wrist guards  Rigid plastic over open cell foam  Deflects impact of FOOSH (fallen outstretched hand) o Absorption Knee/elbow pads  Soft open cell foam covered by hard plastic Footwear Basics Sound Design

There are no optimal running shoes, however certain shoes are optimal for an individual (the best for YOU) LASTS External last is the form on which the shoe is constructed

Last Shape- External (first thing to look at) Curved Last (makes a C shape) Neutral need stability (roll too fast) Medial deviation of forefoot  Can see that the forefoot is more medially than the heel Hollowed out Medial Longitudinal Arch (MLA)  Arch on bottom of foot Neutral foot or high arch

Straight Last Stability  motion control of turning in too much and too fast Solid plantar surface

Extended midsole in MLA Increased base of support  Bigger, flatter, wider Flat footed

Internal last is the interface between the foot and the midsole

Last Shape- Internal Slip Lasting (2 pieces sown together) Solid line of stitching down center of shoe  Used with a neutral/high arch foot; needs more flexibility because feet are firm Increased flexibility  Anyone who requires flexibility Neutral of any kind of shoe that requires flexibility/torsion *Can have a combination of both

Board Lasting Solid board stitched to upper of shoe  Flat feet need support, don’t want them rolling off shoe Increased torsional resistance to pronation  Can’t twist around Better interface for orthotics

Anatomy of a Shoe Upper  All components above the mid sole  Nylon, mesh leather, synthetics  Contains midfoot control technologies (ex. plastic)  Conforms to bony abnormalities  Can be laced different Midsole  Between upper and outsole  Shock absorption or motion control (prevent rolling) o Ex. Nike Air  Densities depend on sport and foot type  Absence of midsole in some shoes that require better “feel” or ball control (soccer shoe) Midsole Material  Polyurethane (PU), EVA, and compressed EVA o PU- grey stability control o EVA- white; full of bubbles (shock absorber) o The darker the colour, the more polyurethane- more dense (adds stability)  PU controls heavier runners  EVA is lighter- when compressed it increases durability Midsole Shape  Tapered from heel to toe, with thickest portion under heel  Rocker sole- curves up at the MTP joint  Stiff rocker soles that start .5cm prox. to MT heads will unload heads and aid forward propulsion (good for rigid feet) o High arch- given a rocker shoe- can roll off easier and not hurt metatarsal head

Outsole  Protective layer on bottom  Protection, durability, flexibility, traction  Use of different rubbers and other materials specific to sport (turf, track, street, etc.)

Footwear Fit

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Length/width- measure both feet and fit largest on weight bearing feet at end of the day (feet swell) Length should not be increased to accommodate width as this will increase lever under toes and cause hyperextension (if too narrow, don’t go a size up  find a wider shoe) To test width place full weight on shoe. Pushing thumbs over top of show should provide ripple. Toe box end of shoe should be 1-1.5cm from end of longest toe Heel- soft enough to absorb energy but not collapse during gait Shock absorption will decrease over time o 25% at 50 miles o 33% after 150 miles o Greater than 60% between 250 and 500 miles! Shape of shoe (last) is classified as straight, curved or semi-curved Rigid foot- curved last with sufficient cushioning Mobile foot- straight last

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 Heel Counter  The stiff material at the back of the shoe built to resist motion in the ankle. More pronation needs stiffer heel counter  Squeeze to see how firm  Should be soft enough to absorb energy but not collapse during gait  At the top of the heel counter is an ankle collar which is intended to protect/cushion the ankle and the Achilles tendon  Should allow for snug fit of heel  If too wide can be filled with felt or heel cup  This is desirable to having a foot that is too tight in the forefoot 3t ype sofs hoe s : 1. Neutral Cushioning: Neutral Foot o High arch o Single density midsole (EVA- shock absorption) o Thermoplastic heel counter o Mild torsional rigidity (can twist/ roll in) o Proprietary cushioning o Slip/curve lasted use for “normal, neutral asymptomatic population” 2.

Stability Shoes: Regular and Mild Over Pronators o Thermoplastic heel counter o Double density midsole PU (stopping pronation) o Moderate/extreme torsional rigidity (lacking it in their foot) o Curved and board lasted for stability

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Motion Control Shoe: Severe Over Pronators and Flat Foot o Thermoplastic heel counter o Triple density midsole o Medial and laterally posted o Extreme torsional rigidity (can’t twist) o Midfoot control o Board lasted (no stitching), straight lasted, no torsional ability o Less rigidity in foot, more there is in the shoe...