简介：Background:Forefootstrike(FFS)andrearfootstrike(RFS)runnersdifferintheirkinematics,forceloadingrates,andjointloadingpatterns,butthetimingoftheirmuscleactivationislessclear.Methods:Fortyrecreationalandhighlytrainedrunnersranatfourspeedsbarefootandshodonamotorizedtreadmill.'Barefoot'runnersworethin,five-toedsocksandshodrunnersworeneutralrunningshoes.Subjectswereinstructedtoruncomfortablyateachspeedwithnoinstructionsaboutfootstrikepatterns.Results:ElevenrunnerslandedwithanFFSwhenbarefootandshodandelevenrunnerslandedwithanRFSwhenbarefootandshod.The18remainingrunnersshiftedfromanFFSwhenbarefoottoanRFSwhenshod(shifters).Shodshiftersranwithalowerstridefrequencyandgreaterstridelengththanallotherrunners.AllFFSrunnerslandedwithmoreplantarflexedanklesandmoreverticallowerlegsatthebeginningofstancecomparedtoRFSrunners.FFSrunnersactivatedtheirplantarflexormuscles11%earlierand10%longerthanRFSrunners.Conclusion:Thisearlierandlongerrelativeactivationoftheplantarrlexorslikelyenhancesthecapacityforthepassivestructuresofthefootandankletostoreelasticenergy,andmayalsoenhancetheperformanceoftheactivemusclebyincreasingthestorageofelasticstrainenergyinthecross-bridaesandactivatedthin.

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简介：Background:Previousstudiesoffootstrikepatternsofdistancerunnersinroadraceshavetypicallyfoundthattheoverwhelmingmajorityofshodrunnersinitiallycontactthegroundontherearfoot.However,noneofthesestudieshasattemptedtoquantifyfootstrikepatternsofbarefootorminimallyshodrunners.Thisstudyclassifiesfootstrikepatternsofbarefootandminimallyshodrunnersinarecreationalroadrace.Methods:High-speedvideofootagewasobtainedof169barefootand42minimallyshoddistancerunnersatthe2011NewYorkCityBarefootRun.Footstrikepatternswereclassifiedforeachrunner,andfrequenciesofforefoot,midfoot,andrearfootstrikingwerecomparedbetweenthebarefootandminimallyshodgroups.Results:Atotalof59.2%ofbarefootrunnerswereforefootstrikers,20.1%weremidfootstrikers,and20.7%wererearfootstrikers.Forminimallyshodrunners,33.3%wereforefootstrikers,19.1%weremidfootstrikers,and47.6%wererearfootstrikers.Footstrikedistributionsforbarefootandminimallyshodrunnersweresignificantlydifferentbothfromoneanotherandfrompreviouslyreportedfootstrikedistributionsofshodroadracers.Conclusion:Footstrikepatternsdifferbetweenbarefootandminimallyshodrunners,withforefootstrikingbeingmorecommon,andrearfootstrikinglesscommoninthebarefootgroup.

简介：Children(5-12years)andadolescents(13-19years)withDownsyndrome(DS)possessasetofhealth,anatomical,physiological,cognitive,andpsycho-socialattributespredisposingthemtolimitationsontheirphysicalfitnessandphysicalactivity(PA)capacities.Thepaucityofstudiesandtheirconflictingfindingspreventaclearunderstandingand/orsubstantiationoftheselimitations.Thepurposeofthisarticlewastoreviewthemeasurement,determinantsandpromotionofphysicalfitnessandPAforyouth(i.e.,childrenandadolescents)withDS.TheexistingbodyofresearchindicatesthatyouthwithDS:1)havelowcardiovascularandmuscularfitness/exercisecapacity;2)demonstrateagreaterprevalenceofoverweightandobesity;3)alargeproportiondonotmeettherecommendedamountofdailyaerobicactivity;and4)theirPAlikelydeclinesthroughchildhoodandintoadolescence.Futureresearchshouldfocuson:1)strengthtestingandtrainingprotocols;2)methodologiestodeterminePAlevels;and3)practicalinterventionstoincreasePA.

简介：Purpose:Toobservetherelativechangeinfoot-strikepattern,pressurecharacteristics,surfaceelectromyography(sEMG)recordings,andstridecharacteristicsinforefootstrikerunnerswearingbothminimalistandtraditionalshoesduringa50-kmrun.Methods:Fourexperiencedminimalistrunnerswereenrolledinthisstudy.Eachrunnerrana50-kmsimulatedruninbothminimalistshoesandtraditionalshoes.Pressuredata,sEMGrecordings,andlimited3Dmotioncapturedatawerecollectedduringtheinitial0.8kmandfinal0.8kmforeachtrial.Results:Threerunnersinthetraditionalshoetypeconditionandonerunnerintheminimalistshoetypeconditiondemonstratedamoreposteriorinitialcontactarea(midfootstrike(MFS)pattern)afterthe50-kmrun.whichwassupportedbyincreasedactivityofthetibialisanteriorinthepre-contaetphase(asperrootmeansquare(RMS)values).Inaddition,inbothpre-andpost-runconditions,therewereincreasedpeakpressuresintheminimalistshoetype,specificallyinthemedialforefoot.Musclefatigueasdefinedbyadecreasedmedianfrequencyobservedinisometric,constantforcecontractionsdidnotcorrespondwithourhypothesisinrelationtotheobservedfootstrikechangepattern.Finally,steprateincreasedandsteplengthdecreasedafterthe50-kmruninbothshoetypeconditions.Conclusion:Morerunnersadoptedamoreposteriorinitialcontactareaafterthe50-kmruninthetraditionalshoetypethanintheminimalistshoetype.Therunnerswhoadoptedamoreposteriorinitialcontactareaweremorecloselyassociatedwithanincreasedmedianfrequencyofthemedialgastrocnemius,whichsuggeststheremaybeachangeinmotorunitrecruitmentpatternduringlong-distance,sustainedvelocityrunning.Theincreasedpeakpressuresobservedinthemedialforefootintheminimalistshoetypemaypredisposetometatarsalstressfracturesinthesettingofimpropertraining.

简介：Purpose:Thisstudyexaminedvariationinfootstriketypes,lowerextremitykinematics,andarchheightandstiffnessamongTarahumaraIndiansfromtheSierraTarahumara.Mexico.Methods:Highspeedvideowasusedtostudythekinematicsof23individuals.13whohabituallyweartraditionalminimalrunningsandals(huaraches).and10whohabituallywearmodern,conventionalrunningshoeswithelevated,cushionedheelsandarchsupport.Measurementsoffootshapeandarchstiffnessweretakenontheseindividualsplusanadditionalsampleof12individuals.Results:MinimallyshodTarahumaraexhibitmuchvariationwith40%primarilyusingmidfootstrikes,30%primarilyusingforefootstrikes,and30%primarilyusingrearfootstrikes.Incontrast,75%oftheconventionallyshodTarahumaraprimarilyusedrearfootstrikes,and25%primarilyusedmidfootstrikes.Individualswhousedforefootormidfootstrikeslandedwithsignificantlymoreplantarflexedankles,flexedknees,andflexedhipsthanrunnerswhousedrearfootstrikes.FootmeasurementsindicatethatconventionallyshodTarahumaraalsohavesignificantlylessstiffarchesthanthosewearingminimalshoes.Conclusion:Thesedatareinforceearlierstudiesthatthereisvariationamongfootstrikepatternsamongminimallyshodrunners,butalsosupportthehypothesisthatfootstiffnessandimportantaspectsofrunningform,includingfootstrike,differbetweenrunnerswhogrowupusingminimalversusmodem,conventionalfootwear.

简介：Background:Investigationsofrunninggaitamongbarefootandpopulationshaverevealedadiversityoffootstrikebehaviors,withsomepreferentiallyemployingarearfootstrike(RFS)asthefoottouchesdownwhileothersemployamidfootstrike(MFS)orforefootstrike(FFS).Here,wereportfootstrikebehaviorandjointanglesamongtraditionalHadzahunter-gathererslivinginNorthernTanzania.Methods:Hadzaadults(n=26)andjuveniles(n=14)ranatarangeofspeeds(adults:mean3.4±0.7m/s,juveniles:mean3.2±0.5m/s)overanoutdoortrackwaywhilebeingrecordedviahigh-speeddigitalvideo.Footstriketype(RFS.MFS.orFFS)andhindlimbsegmentanglesatfootstrikewererecorded.Results:HadzamenpreferentiallyemployedMFS(86.7%ofmen),whileHadzawomenandjuvenilespreferentiallyemployedRFS(90.9%and85.7%ofwomenandjuveniles,respectively).NoFFSwasrecorded.Speed,thepresenceoffootwear(sandalsvs.barefoot),andtrialdurationhadnoeffectonfootstriketype.Conclusion:UnlikeotherhabituallybarefootpopulationswhichpreferFFSwhilerunning.HadzamenpreferredMFS.andHadzawomenandjuvenilespreferredRFS.SexandagedifferencesinfootstrikebehavioramongHadzaadultsmayreflectdifferencesinrunningexperience,withmenlearningtopreferMFSastheyaccumulatemorerunningexperience.