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简介：Purpose:Thepurposeofthisstudywastoexaminetheeffectsofpre-coolingandfluidreplacementwitheithercrushediceorcoldwater.Methods:On2separateoccasions,inacounterbalancedorder,9recreationally-trainedmalesingested1.25g/kg（80–100g）ofeithercrushedice（0.5℃）orcoldwater（4℃）every5minfor30minbeforeexercise.Theyalsoingested2.0g/kg（130–160g）ofthesametreatmentdrinkat15min,30min,and45minafterthecommencementofcyclingtoexhaustionat60%VO2maxuntilvoluntaryexhaustioninahotenvironment（35℃and30%relativehumidity）.Results:Thecyclingtimetoexhaustioninthecrushedicetrial（50.0±12.2min）waslongerthanthecoldwatertrial（42.2±10.1min;p=0.02）.Althoughtherectaltemperaturefellby0.37℃±0.03℃（p=0.01）attheendoftherestingperiodafterthecrushediceingestion,theratesofriseinrectaltemperatureduringtheexerciseperiodwerenotsignificantlydifferentbetweenthese2conditions（crushedice:0.23℃±0.07℃,5min;coldwater:0.22℃±0.07℃,5min;p=0.94）.Conclusion:Crushediceingestionbeforeandduringexerciseinahotenvironmentmaybeapreferredandeffectiveapproachforminimizingthermalstrain,andforimprovingenduranceperformanceascomparedwithcoldwateringestion.

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简介：Purpose：Theaimofthisstudywastoinvestigatetheinfluenceofthecardiorespiratoryfitnesslevelontheresponsetohigh-intensityintervaltraining（HIIT）withanindividuallyadjustedrunningspeedofthesamerelativeintensity.Theevaluationfocusedonacutecardiorespiratoryresponse,postexercisecardiacautonomicmodulation（heartratevariability（HRV））andbiochemicalmarkersofinflammation,oxidativestress,andmuscledamage.Methods：Thirtyparticipantsweredividedinto3subgroups：welltrained,moderatelytrained,anduntrained.Alltheparticipantsperformed30minHIITcomposedof6×2minintervalexercisewithwork-to-reliefratio=1andworkintensity100%ofindividualvelocityatmaximaloxygenconsumption（VO2max）.Acutecardiorespiratoryvariables,postexerciseHRV,lactate,interleukin-6（IL-6）,totalantioxidantcapacity（TAC）,creatinekinase,andmyoglobinupto4hafterHIITweremonitored.Results：Thedifferencesinrelativelyexpressedcardiorespiratoryvariables（heartrate,VO2）duringHIITwereatmostmoderate,withthemostpronouncedbetween-groupdifferencesinabsoluteVO2values.ThedisruptionofthepostexerciseHRVwasthemostpronouncedinuntrainedindividuals,andthisdifferencepersisted1hafterHIIT.ThehighestpostexerciseIL-6andTACconcentrationsandthelowestchangesincreatinekinaseandmyoglobinwererevealedinwell-trainedindividuals.Conclusion：Thehigherfitnesslevelwasassociatedwiththelesspronouncedpostexercisecardiacautonomicchangesandtheirfasterrestoration,evenwhenthereweresimilaracutecardiorespiratoryresponses.ThesefindingsweresimultaneouslyaccompaniedbythehigherpostexerciseIL-6andTACconcentrationsandlesssignificantchangesinmuscledamagebiochemicalmarkersinwell-trainedindividuals.