Background:Accelerometershavebeensuggestedtoprovideadditionalinformationduringthe6-minwalktestwhichmaybeusefulinevaluatingchangesinfunctionalexercisecapacity.TheaimofthestudywastoidentifywhethertheadditionalinformationmeasuredbytheMyWellnessKey~(TM)(MWK)accelerometerduringatreadmill6-minwalktest(t-6MWT)wasrelatedtocurrentlyusedoutcomemeasures.Methods:Fifteenparticipants(9males,6females)performedaself-pacedt-6MWT.RespiratorygasanalysisandwalkingdistanceweremeasuredwhilstwearingtheMWK.Results:Asignificantcorrelationwasestablishedbetweenactivitycountsand6-minwalkdistance(6MWD)(r=-0.847,p<0.001)yetnot6-minwalkwork(6MWW)(r=-0.337,p=0.220).EnergyexpenditureestimatedbytheMWKwasstronglycorrelatedto6MWW(r=0.938,p<0.001)butnot6MWD(r=0.477,p=0.072).TheMWKsignificantlyunderestimatedenergyexpenditure(36.73,CI=33.9-39.7kcal)comparedtogasanalysis(54.35,CI=46.2-61.4kcal)demonstratingpooragreementbetweenthetwoanalyses(Bias=-17.61kcal,Limitsofagreement=-37.4,t2.2kcal).Measurementoftimespentundertakinglight,moderate,andvigorousphysicalactivitywasnotsignificantlydifferent(p>0.05)betweentheMWKandgasanalysis.Conclusion:EstimatedenergyexpenditureprovidedbytheMWKwasstronglycorrelatedto6MWW;however,MWKunderestimatedenergyexpenditureasmeasuredbygasanalysis.TheMWKmayprovideoutcomedatathatsupplementthosecurrentlyprovidedbythe6MWDforfunctionalcapacityassessmentduringthet-6MWT.