gravity defyer evaluation v2.2 defyer evaluation v2.2.pdfgravity defyer footwear – evaluation of...

GRAVITYDEFYERFOOTWEAR–EVALUATIONOFSTATEDBENEFITS1

GRAVITYDEFYERFOOTWEAR

WHITEPAPEREVALUATIONOFSTATEDBENEFITS

August2011


Abstract

ThefocusofthispaperistoquantifyandqualifythebenefitsofGravityDefyershoesonthehuman

bodyduringthegaitcycleandinastaticposition.Thematerialsitedwillcorrelatetheseactionstothebenefitstheseshoesprovidetothepeoplewhowearthem.AnalysisofthecompositionoftheGravityDefyershoeiscrucialtounderstandingthecorrectivefunctiontheshoesprovideandtheresulting

benefits.Aspartofthisexaminationwewillobservethepiecemakeupoftheshoesachieveadirectunderstandingofeachpart’sroleinthereductionofpainandfatigue.

Herein,seriousconsiderationisgiventoheelstrike,forefootstrike,footconditionsandpathologies,posturalalignment,andfatigue.Datarelatingtoshoeconstruction,stability,andcontrolwillalsobethoroughlybrokendowntoexplaintheactualbenefitsandfunctionalityoftheseshoes.Asimple

comparisonofothershoebrandsfeaturingsimilartechnologies(coilsorspringsystems)tothatutilizedinGravityDefyershoesprovidesawealthofdataandfurtherjustifiestheclaimsmadebyGravityDefyer.Significantdataandresearchwasfoundtologicallysubstantiateclaimsofpainrelief,fatigue

reduction,appearingtaller,andanincreaseinadditionalenergy.


Introduction

1.1 EstablishingtheNeedforBiomechanicallySoundFootwear

Fordecadesshoemanufactureshavediscussed,marketedandproducedshoestoaddressconditionsofthehumanfoot.Manyofthesemanufacturesmakeclaimsofcomfort,yetthereisnothingthatmakestheirshoessignificantlydifferentfromtherestoftheindustry.Shoesforcenturieshavefollowedthe

basicpremiseofasolidoutsolewithleatherupper.Theprimarydeviceusedtomakeonebrand’sfootweardistinctfromanotherwasthealterationofthedesignand/ormaterialoftheupperandtheinclusionofmoreandvariedmaterialsusedintheconstructionofthesoleandmidsoleduetoadvances

inchemicalengineeringandadvancedproductionmethods(Poly‐Urethane,EVA,other)Selectingacomfortshoeunderthesecircumstancesisabitlikethechoiceofapplesorapples.

Customshoeshavelongbeenmadeforpeoplewithseriousfootconditionsthroughouttheworld.Someoftheconceptsusedtoproduceamedicalbenefithavebeenincorporated,withvaryingsuccess,intoshoesproducedforthegeneralpublic.Typicallytheseareconsideredtobejustatrendshoeorafad

shoeinsteadofalong‐termsolutiontoanexistingproblem.Ofthoseshoesproducedwiththemedicalconceptbuiltintothem,mostareonthemarketforonlyashortperiodoftimebeforetheirefficacyhas

eitherbeendisprovenorthepubliclosesinterestinthem.GravityDefyerInc.hasproducedGravityDefyershoessince2005.Theyareunlikeanyothershoeonthe

markettoday.Theshoesprovideadirectbenefittotheconsumerandunlikefadproducts,havemaintainedanoverallacceptancebythegeneralpublic.IndesigningandproducingGravityDefyershoes,thecompanyhastakenanapproachuncommontoshoemanufacturers.Theyfocustheirefforts

on1)generalcomfort,2)applyingadvancesinmaterialsandtechnologytobestbenefitthehealthandwell‐beingoftheconsumer,and3)style.

GroundReactionForce

AccordingtotheCenterforDiseaseControl85%ofthegeneralpublicisexperiencingsometypeofbiomechanicaldisease,ofthose85%–thevastmajority–wouldgreatlybenefitfrombiomechanicallycorrectiveshoes:

shoesdesignedtochange,correctandalleviatethesymptomsthesepeopleexperience.TheprimaryobjectivesofbiomechanicallycorrectiveshoesarethereductionofGroundReactionForce(GRF:Theforceexertedbythe

groundonabodyincontactwithit.)andthecorrectionofbodyalignment.Theseconcernsarenotnew,butaddressingthemthroughashoeis.Whilethemajorityoffootwearbrandsfocusonthedispersionofforcethroughthe

useofEVAoranothershockabsorbingmaterial,GravityDefyerhasdevelopedashoethatisalsoamechanicaldevice.Ithasbeenengineeredtoperformtwoprimaryfunctionsfromwhichitsbenefitsarise.


1. ToreducetheaccumulatedimpactdamageoftheGRF.2. Tobalanceandreturnthehumanfoottoaneutralposition,therebycorrectingaspectsofbody

misalignment.Throughtheapplicationofhumanbiomechanicstoshoeconstruction,GravityDefyershoes

demonstratetheabilitytoaddress,changeandmakeshoesatoolthatapersoncanactuallybenefitfromwearing.

1.2 Currentstateofshoemanufacturingindustry

Shoemanufacturinghasgonethroughvastchangesfromwhatwasconsideredagoodcomfortableshoe30yearsago.Cornersareoftencutforcostmanagement;functionandsupportaresacrificedforstyle,

weightandproductiontimehavereplaceddurability.GravityDefyershoesfortunatelydonotadheretothisphilosophy.Theirapproachinproducingashoeistoprovidecomfortandsupportwhilestillencompassingstyleandfunctionality.GravityDefyershoesareconstructedwiththefundamental

platformsharedbyotherqualitycomfortshoes.Whatseparatesthemfromtheircompetitorsistheirapplicationofbiomechanicalprinciplesthatareknowntobenefittheconsumer,yetarenotincorporatedinotherfootwear.

1.3 Contemporarystandardsusedinshoeproduction.

Intheshoeindustry,thecriteriaforagoodcomfortablepairofshoesisconsideredtobecomposedof5

mainpoints:(2,3,4,10,16,20,22,29).

Shank‐Thesolidstabilizingsupportrunningthroughthemiddleoftheshoe,

underthemidsoleand/orupperlayeroftheoutsoledesignedtoreinforcetheshoesstrength.TheShankis(steel,plastic,orcomposite)usedtoprovideadditionalstabilitytothearchaswellcontroltotheheel.(2,3,4,10,16,20,22,29)

HeelCounter‐Thereinforcedposteriorsegmentoftheshoe,whichisdesignedtowraparoundtheheelofthefootandcontrolmovementoftheheel.Thisadditional


materialcreatesanimprovedfit,feelandsupportofthefoot.Thisallowsforgreatcontrolandstabilizationduringthegaitcycle.(2,3,4,10,16,20,22,29)

RoundedToeBox‐Theshoesforefootmustbeshapedtoallowampleroomfor

thetoearea.Thisisaccomplishedbyprovidingadeeperandwidertoeboxthancommonlyusedinfashionfootwearwheresharpanglesandclosefitmaycausenumerouspathologiesincludedhammertoes,clawfoot,bunionsandotherskin

irritations.(2,3,4,10,16,20,22,29)

Genderandethnicvariationsinfootanatomy

RemovableInsole‐Aremovableinsoleisrecommendedforallfootweartoallowtheapplicationofcustomorthoticsandcorrectivedevices.Thisfeatureallowstherewearertomodify,oradjusttheinteriorfitoftheshoeandcorrectforknown

pathologies.(2,3,4,10,16,20,22,29) Breathability‐Theabilityofairtopassthroughthefootweariscalled

breathability.Itcombinestwodesirabletraits,Airpermeabilityandwatervaporpermeability.Breathabilityisadesirablefeatureforhealthandcomfort.Closedfootwearcompoundstheheatgeneratedbyyourbodycausingtemperatureshigher

thanthatoutsidethefootwear.Oncecombinedwithperspiration(moisture),thesepropertiesformanidealenvironmentformicrobialgrowth.Shoesthatfeature


breathabilityarebothmorecomfortableandadvanceproperfoothealth.(2,3,4,10,16,20,22,29)

2.1 GravityDefyerShoes:ASummaryofTheirCompositionandIntendedApplication

BreakingdownthefunctionalityofGravityDefyersshoesstartsbyunderstandingthemaincomponent

thatseparatesthisshoefromthatofothermanufacturers,theTrampolinesystem.

2.2 TheTrampolinesystem

TheTrampolinesystemisashockabsorbingmechanismintegratedwithintheposterior

heelregionofthesole.Itconsistsoffivecomponents:1)amidsolewithmoldedside‐wallsandacavitylocatedbeneaththeheel2)aprimaryshockabsorbingspringorcoil,3)twostabilizingshockabsorbingspringsorcoilsand4)aheelplatewithrubber‐

polymertrampolinesurface.5)thefoot‐bedwhichsupportsthefootandresiststheactionofthetrampolineprovidingadynamicfloatingsupportsystem.

2.2.1 Midsole,MoldedSide‐Walls,TrampolineCavityandShankThemidsoleisconsideredthebodyoftheshoe.Themidsoleofeachshoeismadeof

EVA(Ethylene‐VinylAcetate).Thismaterialisanindustrystandardforthedispersionofforce.InGravityDefyershoes,themidsoleprovidesshockprotectionfromthemid‐footregionthroughthemetatarsalsandtoes.Themidsolehousestheshank.Theshank

extendstothemetatarsalsofthefootallowingforforefootbendandprotectsthefootbylimitingflexationofthearchwhileprovidingadditionalstabilityandcontrolfromtheheelandarchofthewearer.Theheelregionistooledtoformahollowspaceor

trampolinecavitydirectlybeneaththeheel.Theresultantsemi‐rigidsidewallactsasthefoundationforthetrampolinestructure.Thesesidewallsactasasecondarystageinabsorbingshockandwillflexunderextremeforces,furtherreducingGRFandallowsfor

thetransferofforceandmassthroughthesoleoftheshoe,whilenotimpactingthewearerwiththewaveofforceradiatingthroughtheirbody.

2.2.1 PrimaryShockAbsorbersandTwinShockAbsorbingStabilizers


Thespring(orcoil)systemistheprimarydefenseagainstGRFandprovidesmoreenergyreturnthanEVAorothermaterialsusedincontemporaryfootwear.Theysetina

triangularconfigurationandintegratedintotheposteriorheeloftheouterlayerofthetrampolinesole.Asafurtherbenefit,theactionoftheshockabsorberscompensatesforunequalorunevendistributionofweightandpressure.Ifawearerispronetohavefat

padshift(VarusorValgum)(10,22,25)thespringsworkindependentofeachothertoaccommodatethewearer’spressurepattern.Thespringsvaryinresistancebasedontheshoesize(andpresumedweightincreaseofthewearer).Asanexample,asize10

man’sshoeusesabluespring,withacapacityof220psi.Thisspringactsastheprimaryshockabsorber.Tworedsprings,eachwithacapacityof60psiactasstabilizers.Thecombinedliftofthethreespringswithouttakingintoaccounttherubberpolymer’s

elasticpropertiesisapproximately600lbsandprovidesoptimulsupportforapersonofaveragesizeduringmostcommonactivities(standing,walkingandrunning).

2.2.1 TheHeelPlateTheheelplateisan8mmsectionofsolematerialsuspendedonaplateofrubberpolymer.Whendepressed,theheelplateretreatsintotheheelcavityofthemolded

midsole.Duringthisactiontherubberpolymerisstretchedaddingitselasticpotentialenergytotheshockabsorbingforceoftheothershockabsorbingelements.

2.3 TheOutsole

TheoutsoleoftheshoesaretooledandcomposedofEVAorPUtoprovidethebestcontrolonvarioussurfaces.Thecompositionoftheoutsoledictateshowtheshoeinteractswiththe

environmentthroughfriction(grip)andslipresistance.ThesolesofGravityDefyershoesreflectindustrystandardsandpracticesforshoesineachclass,whethertheybeforsportshoesoracasual/dressshoe.Theoutsoleshavenotyetbeenratedforslipresistance,oilorchemical

resistance.

2.4 HeelCounter

TheheelcountersoftheGravityDefyershoesarereinforced.Theyareintheposteriorupperpartoftheshoe.Mostmanufacturersneglectthisimportantfeatureinfootwear.TheheelcountercoversthecalcaneusorheelwhilesupportingtheAchilles.

2.5 ToeBox

ToeboxinGDshoesaredesignedandmanufacturedforcomfort.Generousroomandspaceisgiventotheforefoot.Theshoesaremadeinmedium,wide,andextrawidetoallowforproper

fit.Whilethespacinginthetoeboxallowsforvariationinfootanatomy.FreemovementofthetoesisreinforcedwhilestillholdingthefootinplacewiththevampandQuarter.(10,29)


2.6 RemovableInsoles

RemovableInsolesarefeaturedinallGravityDefyershoes.Thisisimportantbecauseitallowsthewearertochangeouttheinsoleforamedicallyprescribedorthotic,toadjusttheshoefit,ortoextendthelifeoftheshoeiftheinsoleisworndown.TheremovableinsoleinallGravity

DefyershoesismanufacturedfromPU.Theyhaveabuiltupregioninthearchtoprovideadditionalsupportandcontrol.Anaddedfeatureoftheinsoleisthedomepocketcreatedintheheeloftheinsole,directlyunderthecalcaneus.Thisfeaturegivesadditionalcomfortby

improvingheelplacement,centeringandcuppingtheheel.(2,10,16,22,29)*Imageofourinsole

2.6 FitandAdjustability

Duetoalackofeducationandchoice,themajorityofpeopletodaywearill‐fittingshoes.Thisisanimportantfactorrelativetocomfortandmaycontributetothedevelopmentoffoot

pathologies.

2.6.1 FixedSizesGravityDefyershoesaremanufacturedinbothfullandhalfsizesfromsize5‐11female

men7.5‐15andareavailableinarangeofwidthsfrommediumtoxtra‐xtrawide.2.6.2 WidthAdjustability

Twocomponentsacttoprovideaproperfitandfeelforyourfootwear.

2.6.2.1Choiceofclosures.

GravityDefyerscomeinawiderangeofclosuretypesincludingslipon,elasticandlace‐up,butthemostimportanttoindividualsrequiringaproperfitformedicalreasonsisthelace‐upvariety.Lace‐upshoesprovideadjustabilityat

severalpointsalongthearchandarerecommendedforpersonswithdiabetesandothercirculatoryconditions.

2.6.2.2WideandAdjustableWidths.SelectGravityDefyershoeshavebeendesignedwithadditionalwidth.Throughtheadditionofanadjustmentlayer(dubbedthePerfectFitinsole)beneaththe

standardinsole,onemayadjustthefitandfeeloftheshoetobestsuittheirneeds.Thisisagreatfeatureandbenefittowearerswithnarroworslimgirthfeet.

2.7 VentilatedUpperConstruction

GravityDefyershoesmadeofleatherprovideindustrystandardventingthroughpiercingandgrommetswhereapplicable.Athleticshoesusemeshedfabriclayers.Thismeshiscomposedof


crossedgridlayerstoallowpenetrationofairinandoutoftheshoesthroughpredeterminedmeshairholes.Thisfeaturecombineswiththesignificantamountofroominthetoeboxallows

fortheairtomovefreelyinandoutoftheshoes.Theairthatpenetratesintothechamberfromthemidsoleoftheshoeisreleasedthroughtheventopening.

2.7 AVS3VentilationSystem

BothleatherandathleticshoesfeaturetheAVS3VentilationSystem,asystemthatharnessestheexpansionandcontractionofGravityDefyer’suniquetrampolineheeltoformavacuum

pump.Thesystemconsistsofaheelcylinder,channelsthathavebeenmoldedintothemidsole,openventsthatallowairtopassfromtheshoetothesechannels,andaone‐wayvalvelocatedintheheelcylinder.Freshairisdirectlyintroducedfromtheoutsideoftheshoes,always

maintainingthesameconsistencewiththeairtemperatureofthesurroundingarea.Oncompressionoftheheelcylinder,heatedairfromtheshoe’sinteriorisexpelledthroughtheone‐wayvalveinthesidewallofthemidsole.Astheheelcylinderexpands,theone‐wayvalve

closesforcingthevacuumsystemtodrawairfromtheinterioroftheshoe.Thevacuumcreatesnegativepressuresuckinghotairfromtheinterioroftheshoebedandcarriesittowardtheheelcylinder.Thiscyclerepeatswitheverystep.Calculationsindicatethatone8ththeavailable

volumeoftheshoe’sinteriorisexpelledwitheachcycle.(AVS3TechnicalData)

3. BiomechanicalAdvantageOverOtherFootwear

GravityDefyersworkbasedonatrampolineconcept.ThistrampolineislocatedintheposteriorsoleoftheshoesabsorbingtheinitialcontactofGFRwhileallowingtheheelofthewearertocontinuedrivethroughtheheelwithoutfeelingtheimpact.Asecondarybenefitofthisshockabsorbingactionisthe

two‐stagenatureofitscompression.Astheheelplatformretreatsintothemidsoleitcompensates,allowingforbalancedcontactoftheheel.Asthemid‐footandforefootmakecontactthefrontalplainoftheforefootisthenincontactwiththegroundatanequalandflatplane.Thisactionwiththeaddition

oftheinsole,allowsforthewearertomakepropertransferofweightthroughthemetatarsals1st‐5th,loadingthe1stMPT(MetatarsalphalangealJoint)(2,11,25,26),Sesamoids(2,11,25,26),andHallux(2,11,25,26)andreleasingoutofthedistalendofthephalangewhichiswidelyconsideredtheideal

methodofweighttransferandreleaseinthehumanfoot.Asweightistransferredforward,theheelofthewearerispropelledupandforwardbythesprings.


Figure. 3.30. Phases of step (Gage, 1990, p.298)

3.1 WalkingandStandingWalkingandStandingplayamajorpartdaytodayactivitiesthatmostofthepopulationwill

performwitheaseandexperiencelittle‐to‐nodiscomfort.Duringtheseactionswerarelytakeintoconsiderationthedurationandquantityofimpactforceonthehumanbody.Duringthewalkingphaseofthegaitcycle,thehumanbodyisexposedto1.5to3timesthebodyweightof

thewalker(1,10,12,20)Thissignificantpressureincreaseonjoints,tissues,andalignmentofthebodywillcausechangesandalterationinfunctionality.Thiscanandoftendoesleadtotheexperienceofpain,discomfort,andmedicalpathologiesinaprolongedperiodoftime.(6,10,

12)Walkingisanessentialfactorinmaintainingorachievinggoodoverallhealth.Thebenefitsofwalkinghaveshowntobeasbasicasmovementfunctionbutmaygreatlyincreaselifespan.*GraphorTablefromoneofthenotedsites


GravityDefyershoespromotewalkingandallthebenefitattainedbyit.ThesebenefitsareenhancedbyindividualswearingGravityDefyershoesindifferentareas.Asillustratedinthe

imageabove,thenaturalgaitcycleofthehumanbodyisverycomplex.Therearepointsinthegaitcyclewherethehumanbodyhasloadedtheentiremassofthebodyontoanareaassmallajusttheforefootortoes.Aswetakeastepourweightshiftsandourlegsandarmscounter

balanceeachotherandourbodytomaintainanuprightpositionandallowustocontinuetotransferandmoveourbodiesforward.

Whenwearetransferringourweightwewillinitiallyloadtheheelorcalcaneuswithourentireweight,GravityDefyershoesreducetheimpactofthisweightfromthegroundonthecalcaneus.AstheweightcompressesthespringsthesoleabsorbtheimpactofGRFand

dissipatesit.TheremainingimpactforcethatdoestransferupthebodyisagainreducedbythecushioningprovidedbyGravityDefyershoes’Polyurethaneinsoles.Bymaintainingthealignmentofthebodythroughoutthegaitcycleanindividualwillexperiencegreatercomfort,

andeaseofmovement.Thereisthebenefitofthespringreturnorreboundeffect.Thisistheamountofliftorbounda

personwillexperienceduringheelliftorcalcaneuspropulsion.Aftereachheelstrikethespringsystemcompresses,asthesidewallsalsomoveintotheheelandtheGRFisreducedthespringsloadandreleasewiththecalcaneus.Thissendstheforceup,assistingthefootandbodyby

minimizingtheamountofmuscleactivityandenergyneededtopropelthefootandlegforward.Thisreductioninmuscleuseallowsforlongwalksandincreaseddistances.Thebenefitsofthese

resultshaveagreateffectonthephysicalbodyaswellasthementalandemotionalstateofaperson.Thevalueoftheconfidenceandimprovedresultsishardtoquantifyforthepersonandtheiroverallhappiness.

3.2 StandingWheninastaticposturethehumanbodyisdesignedtoworkasaloadedstructure.(1,3,6,7,23)

Theentiremassofthebodyisloadedonthefeet.Thepositionorpostureofthehumanmusculoskeletalhasadirectrelationtothegait.Withoutproperpostureoralignmentthedurationofstaticpositioningwillcausephysicalstressorsthroughoutthebody.Postureand

positioningofthebodyisvitalwhenconsideringconditionsandpathologiesthataffectthestructure.(4,5,6)Variousconditionsbecomeapparentwheninthestaticorstandingpositionandareoftenexperiencedbytheindividual.Somecommonconditionsoftenexperiencedbythe

majorityofthegeneralpublicarecompressionofthejoints,poolingoffluids,swellingandaching,andattimesnumbnessortingling.Theseareallresultsofprolongedpressureonthebody,specificallyfromthelowerlumbar(back)downtothefeet.

InitiallyGravityDefyershoesweredesignedtoaddresstheGRFexperiencedwhenwalkingonhardsurfaces.Theresultofthetrampolineconceptwhenappliedtostandinghasprovento

providegreatbenefitstoanywearerintheshoes.Theamountofenergyexpendedbythebodytostandgreatlystrainsallthemusclesthatholdthebodyinthestandingposition.(4,27,28)


Consideringthatfactthefatiguethatsetsinwilleventuallystarttodiminishtheabilitytoholdthepositioninplaceandtheamountoftimetheindividualwillbeabletostanditsimportantto

alloworprovideanpersonwithanareawheretheycanstandwithminimalamountsofcontactforce.Wecaneasilydeducethisbyapplyingbasicideasandprincipalsofalignment.(4)Ifapersonconsidersthatanindividualstandingonwhatiscommonlyknownasanti‐fatiguemat

reducesandprolongsthedurationoftimethatindividualcanremaininastandingposition.(13,14,21,23,24)Thesematsusepolymersthatcushionthecontactforce(Contactforceistheforceexertedbythegroundonaperson’sbodywhileinastaticorstandingwhichisequalto

theindividual’sweightbeingexertedontotheground)andallowthestandingbodytoincreasetheamountoftimestanding.Itisreasonabletoconsiderthatthebenefitsreceivedwillgreatlydecreasethediscomfortandreducepainwhereconditionsthatcausepainexist.

ApersonwearingGravityDefyershoeswillexperiencetheabilitytoloadfullyonthecalcaneuswithproperalignmentofthebody.Thisisaccomplishedbythewaythespringsysteminteracts

withthebody.Firsttheycompresswiththemassofthebodyloadingdirectlyabovethesprings.Thisgivesthepersonthebenefitofreducingtheloadimpactonthebody,joints,andthemusculoskeletalstructure.Becausetheimpactiscompressedinthespringsandnotthebody,

thebodywillnothavetoexpendenergy,muscleactivityorcompensateforpositionallowingthepersontoremainstandingforlongerperiodsoftime.Personshavingpreviousconditionsaffectingthebodyincluding,pathologies,andnon‐standardhumandevelopmentperhapshave

themosttogain.(4,7,11,19)GravityDefyershoesaddressalignmentbyfirstcompensatingforweightshiftorimbalance.Forexample,ifanindividualhasanoverlypronatedalignmentofthe

calcaneusorinversionofthecalcaneus,(19)thespringwillcompensatefortheimproperdistributionofweight.(4)Thiscorrectionwillallowforamorebalancedstanceallowingtheloadingoftheentirestructuretoholdaneutralpostureforalongerperiodoftime.Theheel

counteroftheshoesandPUinsoleassistbykeepingtheentirefootinplace.Itredistributestheweightfromsolelyontheheeltothearchandmid‐footarea.(16)Thisagainallowsforlessstrainonjoints,improvedcirculationandreducedmusclefatigue.

3.3 ImpactForceContactforceistheforceexertedbythegroundonaperson’sbodywhileinastaticorstanding

whichisequaltotheindividual’sweightbeingexertedontotheground.(14,15,18)ContactForceisparalleledtoGroundForceReaction.(1,9,21)GFRisitselfdefinedasthereturnofenergyorforcefromcontactwiththegroundsurfaceonthebodymorelikelyappliedwhen

walking.(7,)Theeffectsoftheseforceshaveadirecteffectonthesoft‐tissueandskeletalcomponentsofthehumanbody.Theimpactforcescauseoscillationsinthewobblingstructuresofthebody,leadingtoinstability,overcompensation,andvariationofthenaturalfrequenciesin

themusculoskeletalgaitcycle.Studiesshowthefirmnessorrigidityofthesolesofshoesdirectlyfactorintochangesinthetimeofpeakimpactforce.Changesoradaptationsinthemusclestoreducetheresonanceoftheimpactwavehaven’tconclusivelyruledoutsofttissuevibration

withinthemuscle.(9,12,14,15)


Illustrations•A.PeakImpactforcesduringtheGaitcycle.

•B.Theduration(shockwave)ofimpactforceduringGaitcycle.•C.GroundReactionforcerelativetoGaitcycle.


4. GeneralizedPain,FatigueandOtherPathologies

4.1 Fatigue

Fatigueisalackofenergyorexhaustionofthebodyormentalstatecausedbystress.Fatiguecanbeconsideredanaccumulationofmultiplefactorshavingtodowithspecificsourceswhich

canleadtoaneventualbreakdownoftheindividualwhetherphysical,mentalorboth.Intheareaofprolongedstanding,shoescanbeanimportantandintricatepartofreducingorenablingthesestressors.(11,19,23)Ofteninthestandingpositionthealignmentofthebodyisthe

principalcauseofmusclefatigue.Themisalignmentofthestructureorbonesplaceaddedstresstothemusclestoholdthestructureinplace.Priortothemusclesystemexhaustingallenergytherewillbeindicatorssuchassoreness,aching,andsimpleadjustmentstopositioning.Thisis

toallowabreakinthestressonthemuscle.(11,19)GravityDefyershoesaddressfatiguebyactingasaloadmoderatorandallowsthemusculo‐

skeletalsystemtoremainrelaxedforalongerperiodthanotherfootwear.


4.2 Pathologies

Thehumanbodyandfeetaresusceptibletocertainspecificmedicalconditionsfromprolongedwalkingorstanding.Notallpathologiesorconditionsarecausedbythisactionbuttheexistenceofthemwillgreatlyreduceorimpedeonesabilitytoperformbasicnecessaryactionswithgreat

discomfortifatall.

4.2.1HeelPain

HeelPainisorcanoftenbeattributedto3mainsources.

4.2.1.1OverUse

Overuseofthegeneralareaafflictingtheimmediateandsurroundingtissuesandnerves.Constantuseleadstoinflammationofthetissueswhileapplyingpressureonthenervesleadingtotheuncomfortablefeelingofpain.The

constantinflammationofthesetissuescanleadtodamage,sometimespermanent.

4.2.1.2PlantarFasiitis

PlantarFasciitisisthetighteningofinflamedthicktissuesonthe

plantarareaofthehumanfootandtissue.Thiscanbeaverydebilitatingconditionwhich

requirestimetoheal.Commoncorrectionsincludestretching,icing,orthotics,andpropershoes.

Oftenpeopleinextremecasewillbegivencortisonetonumbandreducethepainontheinflamed

tissuesandnerves.(9,10,24,25)

GravityDefyershoeshelpalleviatePFin3basicways.Firstisbyreducingthe

pressurebeingappliedtotheinflamedarea.Thisisaccomplishedbytheabsorptionofpressuretothespecificarea.ThetrampolinesystemwillcompressintothesoleoftheshoediminishingtheGRFonthewearer.The

secondbenefitisthatthewearerwillexperiencesomestretchingofthePlantarFisciatissue.Thestretchingwillgivesomereliefbecausethetissueisexpandingandcontracting.Theactionsofthesetypesofmovementpromotehealingof

theinflamedtissues.ThethirdbenefitfromwearingGravityDefyershoestoanindividualwithPlantarFasciitisisthesupportofthearch.ThisisabenefitbecauseattimesthecauseofthePFisthattheanteriorandposteriortibial

tendonsarenotsupportingthearchandallowingformovement.GravityDefyer


PUinsolessupportthisstructureandreducetheamountofmovementinthearchandpressureonthecalcaneus.Thissupportofthearchwillalsostretchthe

PlantarFasica,againpromotinghealingoftheinflamedtissue.

4.2.1.3HeelorBoneSpurs

He

el

He

elSpursorbonespursareconditionsthatcanbehelpedbyGravityDefyershoes.

Whenapersonwiththisconditiontakesastep,theheelistheinitialpointofcontact.(9,10,24,25)Unfortunatelyfortheindividualthisisareaofthefootbeingeffect.InGravityDefyershoesthisimpactisreducedanddistributed

through‐outtheshoesasthetrampolinesystemabsorbsthepressureandimpactwhilenottransferringittothecalcaneusorheel.Thisalsoallowsthe

individualtowalkwithoutanalteredgate.ThisconditionishelpedbythePUinsolesoftheshoe.ThesoftPUoffersadditionalcushioningnotfoundinothershoesaswellasanarchsupport.Thearchsupportintheinsolepartiallyfillsin

thearchandhelpssupportthestructure.Thesupportgiventothearchreducestheamountofpressurethatwillbeloadedontheheel.Theheelorcalcaneuswillnolongerbeloadedfully.Thisisadirectanddistinctbenefitandfeature

othershoescouldnotofferapersondealingwithspurs.

4.2.4LowerBackPain

Lowerbackpainisoneoftheareasofthebodywherevariousfactorscomeintoplay.Whenanindividualisexperiencingbackpaintheoriginofthepaincancomefromacombinationoffunctioningpartsorfromoneofthecomponentsoftheback.

Understandingthiscanhelpnarrowdownthechoicesofthecause.Thelowerbackiscomposedofthevertebra,disc,nerves,sacrumandsofttissues.Eachindividualareamaybethecauseofdiscomfortorareasmayworkinconjunction

withtheforementionedassociatedpart.

SpursHeelspursareboneygrowthsthatcanbeintheshapeofhooksorspursgrowingontheheelor

calcaneus.Itisaverypainfulconditionthatcanbeconfirmedbyx‐rayandfromsymptom

identificationtheindividualisormaybeexperiencing.


CommonPathologiesofthebackareconsideredtobelumbarstrain,traumaorinjury,discherniation,nervecompressionorpitching,andorarthritis.Theconditionsarealladdressedwithconsiderationofeachindividualpart..(9,10,24,25)Mostcanandare

reducedinpainseveritybythesimpleactofreductionofpressureoftheentirearea.GravityDefyershoeshaveassistedinprovidingaidtosufferersofbackpain.Theability

toalignthebodyintoaneutralcorrectedandloadbearingpositionallowsthebacktoreducestrainonthearea.GravityDefyershoesdothisbyfirstloadingallpressureandweightonthetrampolinesystemwherethecalcaneusrest.Theadjustmentand

correctionofthespringsforweightdisplacementorunbalancehelpstabilizethebodyandallowforproperlowerbodyalignment.Oncethecalcaneusisinaneutralpositionthetalus,tibia,fibula,andfemurallalignabovethem.Byproperlyhavingthelower

limbsalignedthepelvisregionwillalsoloadandalignwiththelowerlimbs.Thiscorrectionofposturewillleadthesacrumandlumbervertebraes1‐5toaligndirectlyabove.Withthischangethepressureandstrainontissues,nervesandmusclesis

reduced. 4.2.3HipPain


Hippainistypicallyconsideredtobeanadvancedagecondition.(9,10,

24,25)Todaywearefindingthathippainisnotalwaysaresultofagingbutmayalsobecausedbywearand

tearonthehipjointandthesurroundingtissues.Themorecommonissuesaremusclestrain,

tendonitis,arthritispain,andsnappinghip.

Ingeneraltheseconditionsarecreatedbyconstantuseofthespecifictissue,muscleorareaduetomisalignmentoroveruse.(9,10,24,25)Inallaspectsoftheseconditionsthediscomfortfromthepaincanleadtomoreseriousissuesifnotaddressed.Gravity

Defyerprovidesthereductionsofthesymptomsbyallowingforbettermovementwithoutpain,improvedalignmentoftheareaandbody,andcondensingthepressureandstrainbeingappliedbyuseinthemisalignedposition.

Thisagainisachievedbytheuseofthetrampolinesystembalancingthefootintotheneutralposition.Oncethealignmentofthepositioniscorrected,thepressureandstrainarerelievedonthetissuesandallowstensiononthemusclestoberelieved.

ByabsorbingtheimpactofGRFonthebodyandjointsthehipisallowedtoloadandflexwithgreatereasyandminimalcompensation.Theaddedbenefitofimproved

muscleefficacyandreducedactivityfreestheareaofoveruse.4.2.3Sciatica

Sciaticaoccurswhenthereispressureordamagetothesciaticnerve.(9,10,24,25)This

nervestartsinthelowerspineandrunsdownthebackofeachleg.Itcontrolsthemusclesat

thebackofthekneeandlowerlegandprovidessensationtothebackofthethigh,partof

thelowerleg,andthesoleofthefoot.Sciaticapaincanvarywidely.

Itmayfeellikeamildtingling,dullache,oraburningsensation.Insomecases,thepain

issevereenoughtomakeapersonunabletomove.Thispainmostoftenoccursononeside.Somepeoplehavesharppaininonepartofthelegorhipandnumbnessinotherparts.Thepainornumbnessmayalsobefeltonthebackofthecalforonthesoleofthe


foot.Theaffectedlegmayfeelweak.Sciaticpainoftenstartsslowlyandmaygetworse,commonlyafterstandingorsitting,atnightatrest,whensneezing,coughing,or

laughing,andwhenbendingorwalkingmorethanafewsteps.GravityDefyershoestakethepressureoffthelowbackareawherethesciaticnerveisoftenaffected.Byadjustingthepostureofanindividualwiththeself‐adjustmentofthe

trampolinesinGravityDefyershoes,apersoncanreducethestrainonthesciaticregion,thelumbarregionoralterpelvicmissalignment.Theimprovementofbody,lumbar,andlimbpositioningaccompaniedbythereliefoftensionofthemuscles

surroundingthesciaticnerverelievesthecompressednerve.Asaresult,painreliefallowstheindividualtoresumeday‐todayactivitieswithminimaldiscomfortandgreatmobility.

4.2.3PainAssociatedwithAgingThehumanbodygrowsandages.Jointsformtheconnectionsbetweenbones.They

providesupportandhelpyoumove.Anydamagetothejointsfromdiseaseorinjurycaninterferewithyourmovementandcausealotofpain.Manydifferentconditionscanleadtopainfuljoints,includingosteoarthritis,rheumatoidarthritis,bursitis,gout,

strains,sprains,andotherinjuries.Jointpainisextremelycommon.Inonenationalsurvey,aboutone‐thirdofadultsreportedhavingjointpainwithinthepast30days.Kneepainwasthemostcommoncomplaint,followedbyshoulderandhippain,but

jointpaincanaffectanypartofyourbody,fromyouranklestoyourshoulders.Asyougetolder,painfuljointsbecomeincreasinglymorecommon.


AstudyperformedbytheUniversityofMalaya,(18)showedthattheolderapersonis,thegreatertheimpactorcontactforceisonthebody.Overaperiodof12monthsit

wasfoundthatsubjectsolderthan40yearsofageexperiencedagreatnumberofareasofdiscomfortorpainascomparedtothesubjectsthatwereunder40yearsofageduringthesimpleactofstanding.Thepercentagesofactualpainseverityalsovaried,

theoldersubjectsexperiencedanywherefrom25to75%morepainthandidtheyoungersubjects. Thisisleadsustospeculatethatanaveragepersonwithminimaltonopersistingconditionswouldlikelyfeelpainanddiscomfortintheareasofmostuse

duringwalkingorstanding.Thecausesmayvary,butconstantandprolongedactivitygenerallyactsastheprimarycatalyst.

TheuseofGravityDefyershoesfortheolderagedemographiccanbeasourceforfreedomandacontinuanceofalifestylethatismoreactive.Withthepropulsionandreductionofimpactforcestheelderuserwouldfeellessdiscomfortandhavemoreenergytobeabletowalkandstand.WiththepopulationoftheUSandtheworldasawholelivinglongerGravityDefyershoesareavitaltooltofreedomandmovement.Thebenefitsanindividualcanreceivearelimitless,includinganadditionofmoreyearsofactivelifestyleswithoutpain.

IfGravityDefyersshoesassistinthealignmentofthepostureandpositionofthebodytoreducepressureandfatigue,onecanconcludethatapersonwouldbenefitby

wearingtheseshoesfornon‐specificjointpainaswell.WhenwearingGravityDefyershoes,thecorrectionofpositioningintheskeletalstructurewillreducethewearonjoints.Thisisaccomplishedbythebody’snaturaldesignedtousethejointsintheir


intendpositionandnotoutofmisalignment.Thetrampolinesystemanditscorrectivecapabilitiescreatethecorrectiveactionnecessarytopretendandaltertheoveruseof

thejoints.

5. ProductComparisons

Therehavebeenpreviousattemptsatcreatingandusingaspringorcoilsysteminashoethatwillprovideabenefittotheweareroftheshoes.ThemorecommonorknownbrandsareSpira,Z‐coil,andtheNovelSpringBoot.Asaspringshoe,theirengineeringdataandcustomertestimonialsprovide

supporttotheclaimsbothmechanicalandanecdotal.Themechanicalpropertiesoftheseindicatesthatthecategoryofbiomechanicalspringshoesoffersa

reductionofGRFatheelstrikeofupto19%withanenergyreturnofupto87%addingtoforwardmotion.

5.1 NovelSpringBoot

NovelSpringBootsweretestedandcomparedtoanaverageshoeonthemarket.Aftertestingonmaleandfemalesubjectsitwasfoundthattherewasareductionoftheimpactwhenrunningonthewearer.TherewasfoundtobeanadjustmenttotheimpactcostofthelowerextremitieswhenwearingtheNovelSpringBootproducts.(27).ThisNovelSpringBootallowedthebodytoreducetheGRF,concludingthatthereisadirectbenefitinwearingashoeconstructedtoabsorbordiminishtheforceofimpact.Theactualbenefittothebodywouldpotentiallyincludefewerinjuriestothecalcaneus(fractures,spurs)(21,23),tissuedamage(plantarfasciitis,Achillestendinitis)(21,23,24),andstructuralimpact(posture,alignment)(4,10,17).Withthisasabaseline,wecanseethattheconceptofthespringshoecanhaveadirectbenefittothewearer.

5.2 ZcoilZ‐coilshoesaretheshoesmostoftenassociatedwithaspringsystem.ThedesignofaZ‐coilisashoeinthePlantarFlexedpositionwitha3‐5inhighspringintheheeloftheshoe.Thisshoeisdesignedtoreducetheimpactofforceonthebodywhilealsoequalizingthepressureonthetotalfootarea.(28)Whentheseshoesweretesteditwasfoundthattheshoesdoreducetheamountofpressurefromprimaryimpact.Theeffectwasnotconclusiveforfastwalking.Thepercentagesdemonstratethattherewas20%lessloadingoftherunnersduringtheirgaitcycle.Thisalsoresultedinabenefittoexcessivepronationorsupination.(10,24,28,29)Studiesprovidepositiveresults.CSULBfoundthatmaximummeanpressurewaslowerby18%inastandardgaitvelocity.Themaximumforcewasreducedbyarangeof13‐19%inafastvelocitygaitcycle.Theactualbenefitthatcouldbeappliedtothehumanbodyfromthisreportisthat,GRFis


notcausingtheusualamountofdamageandimpactwavethroughoutthebodyasitdoeswhenwearingastandardbrandofshoes.

5.3 SpiraSpiradesignedashoethatplacedaluminumspringsintotheheelandtheforefootareasofthemidsole.ThiswasaccomplishedbytoolingintotheEVAbasemidsole.Oncetheareawasclearedout,aplasticbottomcoverwasplacedintothesole.Thisplasticwasmoldedtoholdthespringsinplacewithdeterminedspringmolds.Withthespringsinplace,anadditionaltopplasticwasplacedonthemidsole,whichisthencoveredwiththeinnersoleoftheshoe.Thedesignwastoabsorbtheimpactontheheelaswellasontheforefoot,whichwasnamedWaveSpringTechnology.SpirashoesandtheirWaveSpringtechnologystudieswereperformedbyMichiganStateUniversity,CollegeofEngineeringandLaboratory.ThepurposeofthestudywastoidentifyiftherewasanactualimpactreductionofGRFonthehumanfootwhenwalkingandorjumping.Inthereportitwasfoundthat20%ofthebodyweightimpactofanindividualwasreduced.Thespringsystemalsoreturned87‐96%oftheenergytothewearer.5.4 MBTMBTshoesorRockerbottomshoesareshoesdesignedwitharollingorroundedsole.Thissoleisdesignedtoextendfromtheheelorcalcaneusthroughtothedistalendofthephalangesortoes.ThedifferencewithMBTproducedshoesisthatintheheelofthesole,thereisacushionpadorcelonpadthatabsorbstheimpactforceandtransfersitthroughthesole.ThisallowstheweartoexperienceareductioninjointpainandGRFissues.InacasestudyitwasfoundthatMBTshoeshelpreducetheimpactforceandpainonwearswithkneejointarthritis.Therewasareductionof16.6%inthefirst3weeks(30,TheeffectivenessofMBTshoes…)andatotalof25.6%bytheendofthe12weekstudy(30).Therewasalsotheadditionalbenefitofstrengthincreaseinthelowerlegmuscles,improvedbalanceandperformance,anddurationofworkoutperiods.Theonlygroupthatdidnotseethesameresultswasthegroupthatwasobeseoroverweight.Forthisgroupthereductionwasminimal,resultinginthecontinuedeffectsofOsteoarthritisoftheknee.

Thoughthesethreeshoes(NovelSpringBoot,Z‐Coil,SpiraandMBT)differinconstructionandapplication,itisclearthattheresultswouldbequitesimilarandvalidatetheirpotentialmedicalapplication.Byreducingtheforcethatcausepain,activatinganddeactivatingmusclegroups,andmaintainingbodyalignmentthroughbalanceandposturepeoplecangreatlybenefitbywearingGravityDefyershoes.ShoessuchasGravityDefyerofferamechanicaladvantageoverstandardshoes.Theyarebiomechanicallyengineeredforthereductionofpressure,controlofthefoot,andmaintenanceofproperalignmentofthelowerbodybenefitscanbeeasilyachievedbythewearingoftheshoesalone.


6.Conclusion

Resultsfromindividualarethebestgageforunderstandingifaproductisworkingornot.GravityDefyershoespasstheeyetestoncomparisontotheaverageshoeanddirectcompetitorfeatureshoesonthe

markettoday.Theconceptofdesigningashoewithbiomechanicsofwalkingandtheeffectsofstaticpositioningonthebodygreatlychangewhatandhowshoesshouldbemade.GravityDefyersshoeshavejumpedaheadofthetypicalshoeplatformandarechangingthewayweseefunctionalshoes

today.Changingwhatapersonfeelsandhowtheirfoot,legandbodymoveduringthegaitcycleisanundertakingthatcanonlybeachievedbycreatingaproductthatactuallyworksandisbeneficial.

GravityDefyershoesaddressamajorityofconditionsthattheaveragepersonexperiencesandwillfacewhenstandingorwalking.Ifthisshoesandcompanycontinuetoprovidetheresultsthattheycurrentlyofferthewearer,theshoeindustrywillhavetochangehowshoesaredesignedanddeveloped.

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