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Objective Weaimedtoinvestigatedynamicchangesofphosphatemetabolitelevelsinexercisingquadricepsofhealthyyoung Chinesevolunteersusing31PMagneticResonanceSpectroscopy(31P-MRS)controlledbyacustombuiltquantitativesystem,and tostudythedifferencesbetweenmaleandfemale. Methods Atotalof19volunteers(11maleand8female),maleaged21-25yr(mean23.30±1.25yr)andfemaleaged22-24yr(mean23.57±0.79yr),performedknee-extendingexcisesusingcustombuiltexercisesystemwhilelyingproneinPhilips3T MagneticResonance(MR)scanner(Achieva3.0TTX,best,theNetherlands).The31P-MRScoilwasfirmlyplacedunderthemiddle ofquadriceps.31P-MRSmeasurementsofinorganicphosphate(Pi),phosphocreatine(PCr)andadenosinetriphosphate(ATP) wereacquiredfromquadricepswhilesubjectswereinastateofpre-,during-andpost-exercise.ThePCr,Pi,PCr/Pi,PCr/ATP,pH, work/energycostratio(WE),kPCrandoxidativecapacityofmaleandfemalewerecalculatedrespectively. Results TheexerciseloadandWEoffemalewaslessthanmale(P=0.040,P=0.002).Therewerenosignificantdifferencesbetween maleandfemaleforphosphorousmetaboliteandpHlevelpre-exerciseandattheendofexercise.Attheendofexercise,thepH levelreducedcomparedtopre-exerciseinbothtwogroups,andtheATPconcentrationofmalewashigherthanfemaleatthe endofexercise(P=0.035).ThePCrandATPconcentrationdecreasedattheendofexercise,however,onlythatoffemalehad significantdifferencescomparedtopre-exercise(P=0.018,P=0.012).Besides,thereweresharpdeclineinPCr/Piratioduring exercise,thefemalewaslowerthanmale(P=0.047),meantime,thePCr/ATPwasopposite(P=0.025).ThePCr/Piratiohadthe significantdifferencesamongdifferentphases.PCrrecoverycurvepredictedbymonoexponentialfitformaleandfemalegroups. ThekPCrandoxidativecapacityhadnodifferencesbetweenmaleandfemale. Conclusions Inthisstudy,weemployeddynamic31P-MRScontrolledbyMRcompatiblequantitativeforcecontrolsystemtofind thattherewasahigherenergytransferefficientandWEofmaleinexercise.Thistechnologycouldprovidesacomprehensive understandingofhighenergyphosphatemetabolismdifferencesbetweenmaleandfemaleinconjunctionswithhistochemical andbiochemicalstudies.