CANUNCLASSIFIED Lightarmouredvehicle(LAV)occupantseated postures Capt.GabrielleChafe CaptTommyPoirier DRDC–ValcartierResearchCentre CplOlivierHamel CanadianArmedForces AdrienneSy DRDC–TorontoResearchCentre ThebodyofthisCANUNCLASSIFIEDdocumentdoesnotcontaintherequiredsecuritybannersaccordingtoDNDsecurity standards.However,itmustbetreatedasCANUNCLASSIFIEDandprotectedappropriatelybasedonthetermsandconditions specifiedonthecoveringpage. DefenceResearchandDevelopment Canada ReferenceDocument DRDC-RDDC-2020-D029 June 2020 CANUNCLASSIFIED CANUNCLASSIFIED IMPORTANTINFORMATIVESTATEMENTS ThisdocumentwasreviewedforControlledGoodsbyDefenceResearchandDevelopmentCanada(DRDC)usingtheScheduleto theDefenceProductionAct. Disclaimer:ThispublicationwaspreparedbyDefenceResearchandDevelopmentCanadaanagencyoftheDepartmentof NationalDefence.Theinformationcontainedinthispublicationhasbeenderivedanddeterminedthroughbestpracticeand adherencetothehigheststandardsofresponsibleconductofscientificresearch.Thisinformationisintendedfortheuseofthe DepartmentofNationalDefence,theCanadianArmedForces(“Canada”)andPublicSafetypartnersand,aspermitted,maybe sharedwithacademia,industry,Canada’sallies,andthepublic(“ThirdParties”).Anyuseby,oranyrelianceonordecisionsmade basedonthispublicationbyThirdParties,aredoneattheirownriskandresponsibility.Canadadoesnotassumeanyliabilityfor anydamagesorlosseswhichmayarisefromanyuseof,orrelianceon,thepublication. ThedatacollectedaspartofthisstudywasapprovedeitherbyDefenceResearchandDevelopmentCanada’sHumanResearch EthicsBoardorbytheDirectorGeneralMilitaryPersonnelResearch&Analysis’SocialScienceResearchReviewBoard. Endorsementstatement:ThispublicationhasbeenpublishedbytheEditorialOfficeofDefenceResearchandDevelopment Canada,anagencyoftheDepartmentofNationalDefenceofCanada.Inquiriescanbesentto: [email protected]. Templateinuse:EOPublishingAppforSR-RD-ECEng2018-12-19_v1(newdisclaimer).dotm © HerMajestytheQueeninRightofCanada(DepartmentofNationalDefence),2020 © SaMajestélaReineendroitduCanada(MinistèredelaDéfensenationale),2020 CANUNCLASSIFIED Abstract Militaryvehicles havethedistinction oftransportingfully kittedsoldiers.The seatedpostures, and the influence of personal protective equipment(PPE)tosoldier seated posturesin light armoured vehicles (LAV)werenotwellunderstood.Thisstudylookedattheseatedposturechangesthatoccurwhensoldiers were wearing their PPEin three different LAV (LAV III, LAV 6 and LAV LORIT) while seated in three seats (passenger, driver and turret). A total of 23 male participants were monitored with inertial accelerometerstodeterminebodypostureangleswhileseatedinLAVseats.Seatedposturechangeswere evaluatedwithdifferentlevelsofPPE,whileseatedinthethreeseatswithinthethreeLAV.Statistically significantdifferenceswerefoundbetweeninteractionsinvolvingPPEandvehicleseats.Participantseated postures were characterizedshowingdifferencesbetweenthe different LAV seat designs. Footrest use effectsonparticipantseatedpostureswereevaluatedwithaparticipantsubgroup(n=12).Participantseated postures with footrest use resulted in lumbar kyphosis. The unsupported spinal curvature of another 30participantswereevaluatedwithaValedo®Shapespinalmouse.Footrestusewasre-evaluatedwiththis tool,andshowedasignificantincreaseinlumbarkyphosis,andanincreaseinpelvictiltextension. DRDC-RDDC-2020-D029 i Résumé Les véhicules militaires ont laparticularité de transporter des soldats en tenue complète. Les postures assisesetl’influencedel’équipementdeprotectionindividuelle(EPI)surlapostureassisedessoldatsdans un véhicule blindé léger (VBL) n’étaient pas bien comprises. La présente étude visait à examiner les changementsobservésdanslapostureassisechezlessoldatsquiportentleurEPIdanstroisdifférentsVBL (VBLIII,VBL6etVBLLORIT)selonleurpositiondanslevéhicule(c’est-à-direlesiègedupassager,le siègeduconducteuretlesiègedelatourelle).Autotal,23participantsdesexemasculinontétésuivisau moyend’accéléromètresinertielsafindedéterminerlesanglesd’inclinaisondeleurposturealorsqu’ils étaientassisdansleVBL.Leschangementsobservésdanslapostureassiseontétéévaluésenfonctiondu port de différents niveaux d’EPI, et ce, pour chacun des trois sièges dans le VBL. Des différences statistiquementsignificativesontétéconstatéesquantauxinteractionsentrel’EPIetlesiègeoccupédans levéhicule.Lesposturesassisesdesparticipantsontétécaractériséesselonlesdifférencesrelativesàla conception des sièges de VBL. L’effet de l’utilisation d’un repose-pieds sur la posture assise des participantsaétéévaluéauprèsd’unsous-groupedeparticipants(n=12).Chezlesparticipantsutilisantun repose-pieds,lapostureassiseaprovoquéunecyphoselombaire.Lacourburedelacolonnevertébralede 30autresparticipantsenpositionsansappuiaétéévaluéeaumoyend’undispositifValedoMDShapeSpinal Mouse.L’utilisationd’unrepose-piedsaétéréévaluéeàl’aidedecetoutil,cequiarévéléuneaugmentation significativedelacyphoselombaireetuneaugmentationdel’inclinaisondubassinenextension. ii DRDC-RDDC-2020-D029 Tableofcontents Abstract ................................ ... i Résumé ................................ ... ii Tableofcontents ............................... iii Listoffigures ................................ v Listoftables................................ vii Acknowledgements .............................. viii 1 Introduction ................................ 1 2 Methods................................ .. 3 2.1 Participants .............................. 3 2.2 Anthropometry ............................. 3 2.2.1 Instruments............................ 3 2.2.2 Measurements........................... 3 2.3 Seatedpostureangles........................... 4 2.3.1 Vehicleseats ........................... 4 2.3.2 Clothingconditions......................... 6 2.3.3 Accelerometerplacement ...................... 7 2.4 Seatedspinecurvaturemeasurements..................... 8 2.5 Datamanipulation........................... 10 2.5.1 Postureangles.......................... 10 2.5.2 Spinalmouseangles ....................... 12 3 Results ................................ 13 3.1 Semi-clothedanthropometricdata ..................... 13 3.2 Participantseatedpostureangles ..................... 13 3.2.1 DifferentLAVcomparisons .................... 13 3.2.1.1 Participantpostureswhileseatedinpassengerseat......... 14 3.2.1.2 Participantpostureswhileseatedindriverseat .......... 15 3.2.1.3 Participantpostureswhileseatedinturretseat .......... 15 3.2.2 DifferentseatcomparisonswithinaLAV ............... 15 3.2.2.1 ParticipantposturesinLAVIIIseats.............. 17 3.2.2.2 ParticipantposturesinLAV6seats .............. 17 3.2.2.3 ParticipantposturesinLAVLORITseats ............ 18 3.2.3 Differentclothingcomparisons ................... 18 3.2.4 Differentlegpositions....................... 22 3.3 Seatedspinalcurvature ......................... 23 3.3.1 Elevatedlegcomparison...................... 25 4 Discussion ................................ 28 4.1 Participantseatedpostureangles ..................... 28 DRDC-RDDC-2020-D029 iii 4.1.1 BetweenLAV.......................... 28 4.1.1.1 Seatedinpassengerseat .................. 28 4.1.1.2 Seatedindriverseat .................... 29 4.1.1.3 Seatedinturretseat .................... 30 4.1.2 Betweenseatswithinavehicle ................... 30 4.1.2.1 Sittingindriverseatcomparedtopassengerseat ......... 31 4.1.2.2 Sittinginthedriverseatcomparedtoturretseat.......... 31 4.1.2.3 Sittinginthepassengerseatcomparedtoturretseat ........ 32 4.1.3 Betweenclothingconditions .................... 32 4.1.4 Footplacementcomparison..................... 34 4.2 Seatedspinalcurvature ......................... 35 4.3 Limitations ............................. 36 5 Conclusion................................ 37 References ................................ 38 Listofsymbols/abbreviations/acronyms/initialisms .................. 40 iv DRDC-RDDC-2020-D029 Listoffigures Figure1: LightArmouredVehicle6.......................... 1 Figure2: LAVpassengerseatingA)LAVIII,B)LAV6andC)LAVLORIT. ........ 4 Figure3: PassengerseatinginLAVLORITwithA)feetonseatfootrestandB)feetonfootrest oftheseatacross.............................. 5 Figure4: LAVdriverseatingA)LAVIII,B)LAV6andC)LAVLORIT........... 5 Figure5: LAVturretseatA)LAV6,B)LAVLORITsideviewand,C)LAVLORITfront view................................. .. 6 Figure6: ClothingconditionsshowingA)baseline,B)helmet,FPVandtacticalvestin passengerseat,andC)helmetandFPVinturretanddriverseats(notacticalvest). .. 7 Figure7: AccelerometerplacementinA)C7vertebraarea(topaccelerometer)andL5vertebra area(loweraccelerometer),andB)rightthigh,rightmid-calfandtopofrightboot. .. 7 Figure8: Spinalmousemeasurementofparticipantinneutralseatedposture.......... 8 Figure9: SeatedposturesduringspinalmousemeasurementsA)ISO90degrees,B)forward lean,C)backwardleanandD)raisedlegs(footrest).Graphicsdesignby CaptTommyPoirier. ........................... 9 Figure10: Positiveanglesindicatekyphosis,andnegativeanglesindicatelordosisinthesagittal planeofthespine.GraphicsdesignbySarahTierney. .............. 9 Figure11: Graphicdepictionofaccelerometeranglerepresentationasrelativetotheuppertorso andhead(bluefigures). ......................... 11 Figure12: ExampleofExceltransformationofbodysegmentanglesrelativetoISO90posture (conditionzero). ............................ 11 Figure13: ParticipantwearingPPEPseatedposturegroupmeanangles±stdevwhileseatedon theA)passenger,B)driverandC)turretseatofLAV.Statisticalsignificance p≤0.015denotedwith**.*Therewasanaccelerometermalfunctionatthebootfor oneparticipant,nforLAV6andLAVLORITatbootwasonelessthanreported(i.e.,Turret