简介：<正>Background:Increasingcaloricexpenditureinphysicaleducationisconsideredaneffectiveschool-basedapproachtoaddressingthechildobesityepidemic.Thisstudywasdesignedtodeterminesynergisticinfluencesofstudentcharacteristicsandlessonfactorsoncaloricexpenditureinelementaryandmiddleschoolphysicaleducation.Methods:Thestudyusedamulti-leveldesign.Level-1factorsincludedpersonalcharacteristics:age,gender,andbodymassindex.Level-2factorsincludedlessonlength,content,andschoollevel.BasedontheCenterforDiseaseControlandPreventionage—genderadjustedgrowthchart,studentsin87classesfrom14elementaryand15middleschoolswerepre-screenedinto"Overweight","Healthyweight",or"Thin"groups.Oneboyandonegirlwererandomlyselectedfromeachgroupineachclassasdataproviders(264elementaryand294middleschoolstudents).Caloricexpenditurewasmeasuredin243physicaleducationlessonsusingaccelerometers.Results:Analysisofvariancerevealedandhierarchicallinearmodelingconfirmedseparateagebybodymassindex,agebygender,andcontentbylesson—lengthinteractioneffects,suggestingthatthepersonalandlessonfactorsinfluencedcaloricexpenditureindependently.Oldermaleandheavierstudentsburnedmorecaloriesinalllessons.Studentsburnedmorecaloriesin45—60minsportskillorfitnesslessonsthaninshorter(30min)orlonger(75—90min)gameormulti-activitylessons.Conclusions:Thehypothesizedcross-levelinteractionwasnotobservedinthedata.Caloricexpenditurecanbeoptimizedin45—60minsportskillorfitnessdevelopmentlessons.Itcanberecommendedthatschoolsadopt45—60minlessonlengthandprovideskillandfitnessdevelopmenttasksinphysicaleducationtomaximizecaloricexpenditure.

简介：到hamstring的BackgroundInjuries在职业cricketers是相对普通的(因为他们在许多队运动)并且自从2006.MethodsThis学习分析了发生，在板球的T20时代(20-over比赛的介绍)在发生增加了喻摧毁在各种各样的精英男性比赛的损害在一个20年的时期上打字(到2014-2015季节的1995-1996)。风险因素为喻摧毁紧张用逻辑回归分析technique.ResultsThere是的multivariate被估计276比赛时间损失喻摧毁在州或国家的运动员水平，170发生在40,145运动员火柴之一设置的澳大利亚人在一个20年的时期上记录的损害。比赛发作率的全面的率是22.5喻摧毁损害每1000队天。快保龄发作损害每1000队天是以10.9损害的率的最高的子范畴，尽管打的发作损害在50-over(一天)是特别地普通的国际比赛。在逻辑回归分析的重要风险因素，除了喻摧毁损害历史，正在是快bowler亲戚风险(RR)2.5(95%信心间隔(CI)：1.3-4.5)并且在澳大利亚RR2.3玩一场比赛(95%CI：1.3-3.9).ConclusionFastbowlers承受更多喻摧毁损害比在板球的另外的玩的角色，特别地在头等(多天)上板球。Batsmen是更可能的变得在50-over(一天)受伤了板球。在澳大利亚玩(与海外地点相比)导致增加的风险喻摧毁损害。

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简介：<正>Hamstringstrainsareoneofmostcommonsportsinjuries.Thepurposeofthisliteraturereviewistosummarizestudiesonhamstringstraininjuryrate,mechanism,andriskfactorsinthelastseveraldecadeswithafocusonthepreventionandrehabilitationofthisinjury.Hamstringinjurycommonlyoccursinsportingeventsinwhichhighspeedsprintingandkickingarefrequentlyperformed,suchasAustralianfootball.Englishrugby,Americanfootball,andsoccer.Basicsciencestudieshavedemonstratedthatamusclestraininjuryoccursduetoexcessivestrainineccentriccontractioninsteadofforce,andthatelongationspeedanddurationofactivationbeforeeccentriccontractionaffecttheseverityoftheinjury.Hamstringstraininjuryislikelytooccurduringthelateswingphaseandlatestancephaseofsprintrunning.Shortenedoptimummusclelength,lackofmuscleflexibility,strengthimbalance,insufficientwarm-up,fatigue,lowerbackinjury,poorlumbarposture,andincreasedmuscleneuraltensionhavebeenidentifiedasmodifiableriskfactorswhilemusclecompositions,age,race,andpreviousinjuriesarenon-modifiableriskfactors.Thetheoreticalbasisofsomeoftheseriskfactors,however,islacking,andtheresultsofclinicalstudiesontheseriskfactorsareinconsistent.Futurestudiesareneededtoestablishthecause-and-effectrelationshipsbetweenthoseproposedriskfactorsandtheinjury.

简介：<正>Background:Significanteffortshavebeenmadetoidentifymodifiableriskfactorsofnon-contactanteriorcruciateligament(ACL)injuriesinmaleandfemaleathletes.However,currentliteratureontheriskfactorsforACLinjuryarepurelydescriptive.Anunderstandingofbiomechanicalrelationshipbetweenriskandriskfactorsofthenon-contactACLinjuryisnecessarytodevelopeffectivepreventionprograms.Purpose:Tocomparelowerextremitykinematicsandkineticsbetweentrialswithandwithoutnon-contactACLinjuriesandtodetermineifanydifferenceexistsbetweenmaleandfemaletrialswithnon-contactACLinjuriesregardingthelowerextremitymotionpatterns.Methods:Inthiscomputersimulationstudy,astochasticbiomechanicalmodelwasusedtoestimatetheACLloadingatthetimeofpeakposteriorgroundreactionforce(GRF)duringlandingofthestop-jumptask.MonteCarlosimulationswereperformedtosimulatetheACLinjurieswithrepeatedrandomsamplesofindependentvariables.Thedistributionsofindependentvariablesweredeterminedfrominvivolaboratorydataof40maleand40femalerecreationalathletes.Results:Inthesimulatedinjuredtrials,bothmaleandfemaleathleteshadsignificantlysmallerkneeflexionangles,greaternormalizedpeakposteriorandverticalGRF.greaterkneevalgusmoment,greaterpatellatendonforce,greaterquadricepsforce,greaterkneeextensionmoment.andgreaterproximaltibiaanteriorshearforceincomparisontothesimulateduninjuredtrials.Nosignificantdifferencewasfoundbetweengendersinanyoftheselectedbiomechanicalvariablesinthetrialswithsimulatednon-contactACLinjuries.Conclusion:Smallkneeflexionangle,largeposteriorGRF.andlargekneevalgusmomentareriskfactorsofnon-contactACLinjurydeterminedbyastochasticbiomechanicalmodelwithacause-and-effectrelationship.

简介：Background:Studieshaveindicatedthatthereisapositiveandindirectrelationshipbetweenphysicalactivity(PA)andqualityoflife(QoL).Thecurrentstudyexaminedthisrelationshipthroughasocialcognitivemodelwithconsiderationtotheintermediaryeffectsofexerciseself-efficacy,andphysical(PCS,physicalcomponentsummary)andpsychological(MCS,mentalcomponentsummary)health.Additionally,thismodelwaswidenedtoincludeconceptsfromtheecologicaltheory,andanycausalassociationsamongneighborhoodenvironment,PA,andQoL.Methods:Sixhundredandeighty-fourphysicallyactiveadults(39.16±13.52years,mean±SD),livinginAthens,Greece,completedaseriesofquestionnairesmeasuringPA,QoL,exerciseself-efficacy,PCS,MCS,neighborhoodenvironment,andfamilyandfriendsupportforPA.Theexaminedmodelswereanalyzedusingstructuralequationmodeling.Results:Thesocialcognitiveandecologicalmodelsprovedtobeofappropriatefit.Withinthesocialcognitivemodel,PApositivelyaffectedQoLthroughthemediatingeffectsofexerciseself-efficacy,PCS,andMCS.Withregardstotheecologicalmodel,neighborhoodenvironmentpositivelyinfluencedQoLthroughtheintermediaryeffectsoffamilysupportforPA,exerciseself-efficacy,PA,PCS,andMCS.Conclusion:Resultsindicatedthatthemostimportantmediatorsintheexaminedmodelswereexerciseself-efficacyandhealth.Further,findingsdemonstratedtheroleofneighborhoodenvironmentinenhancingPAandQoL.Futurestudiesshouldbecarriedoutapplyinglongitudinaldataforabetterunderstandingoftheseassociationsovertime.

简介：Background:Marginalchangesintheexecutionofcompetitivesportsmovementscanrepresentasignificantchangeforperformancesuccess.However,suchdifferencesmayemergeonlyatcertainexecutionintensitiesandarenoteasilydetectablethroughconventionalbiomechanicaltechniques.Thisstudyaimedtoinvestigateifandhowcompetitionstandardandprogressionspeedaffectracewalkingkinematicsfrombothaconventionalandacoordinationvariabilityperspective.Methods:Fifteenexperiencedathletesdividedintothreegroups(elite,international,andnational)werestudiedwhileracewalkingonatreadmillattwodifferentspeeds(12.0and15.5km/h).Basicgaitparameters,theangulardisplacementofthepelvisandlowerlimbs,andthevariabilityincontinuousrelativephasebetweensixdifferentjointcouplingswereanalyzed.Results:Mostofthespatio-temporal,kinematic,andcoordinationvariabilitymeasuresprovedsensitivetothechangeinspeed.Conversely,non-lineardynamicsmeasureshighlighteddifferencesbetweenathletesofdifferentcompetitionstandardwhenconventionalanalyticaltoolswerenotabletodiscriminatebetweendifferentskilllevels.Continuousrelativephasevariabilitywashigherfornationallevelathletesthaninternationalandeliteintwocouplings(pelvisobliquity—hipflex/extensionandpelvisrotation—ankledorsi/plantarflexion)andgaitphases(earlystanceforthefirstcoupling,propulsivephaseforthesecond)thataredeemedfundamentalforcorrecttechniqueandperformance.Conclusion:Measuresofcoordinationvariabilityshowedtobeamoresensitivetoolforthefinedetectionofskill-dependentfactorsincompetitiveracewalking,andshowedgoodpotentialforbeingintegratedintheassessmentandmonitoringofsportsmotorabilities.

简介：Purpose:Arandomized,controlledtrialwasconductedtodeterminewhethera6-weeklowcaloriedietandaerobicexerciseinterventioncouldaltermetabolicsyndrome(MetS)riskfactorsinpre-pubescentobeseChinesechildren.Methods:Thesubjectswererandomizedintodietandexercise(DE)andcontrol(C)groups.TheDEgroupingested1600-2000kcal/dayadjustedtoeachparticipant’sbasalmetabolicrate,andengagedinhigh-volumeaerobicexercise(6days/week,twicedaily,for3hpersession)for6weeks.Atotalof215obesechildrenbetweentheagesof11and13yearswererecruitedintothestudy,with167subjects(DE,n=95;C,n=72)completingallphases.Pre-andpost-studymeasuresincludedbodyweight,bodymassindex,waistcircumference,bodyfatpercentage,bloodpressureandotherMetS-relatedmarkersfromfastingbloodsamples(serumcholesterol,triglycerides,insulin,andglucose).Results:Comparedtocontrols,theDEsubjectsexperiencedsignificantlyreducedlevelsforalloutcomemarkers(p<0.05),exceptforfastingbloodglucoseinboys(p=0.09).Conclusion:Anintensive,6-weekdietandexerciseinterventionhadfavorableeffectsinalteringMetSriskfactorsinobeseChinesechildrenaged11to13.